Salman Abedi, 22, has been identified as the attacker who detonated a suicide bomb at the Manchester Arena at the end of an Ariana Grande concert, killing himself and at least 22 people, while wounding at least 59 others, Greater Manchester Police say.

Police Chief Constable Ian Hopkins confirmed his identity during a press conference Tuesday. He was born in Britain, authorities said.

Abedi is believed to have used an improvised explosive device, police said. ISIS has claimed responsibility for the attack. NBC News reported Abedi name could actually be spelled Salmon Ramadan Abedi.

CORRECTION: CBS News can confirm suspected Manchester attacker is 23-year-old Salman Abedi https://t.co/OtAmmxHRzF pic.twitter.com/vWYlZrenyB — CBS News (@CBSNews) May 23, 2017

Witnesses said a loud explosion was followed by screams, panic and a stampede of people trying to leave the crowded building, which is one of the largest indoor arenas in the world.

Ariana Grande was not among those injured, her representatives said. The incident was reported about 10:30 p.m. local time, after Grande left the stage and houselights came on, while people were beginning to exit the arena. About 20,000 people were in attendance at the sold-out show, including many teenagers and young people who came to see the pop star perform.

North West Ambulance, the local medical service, said it has taken 59 casualties from the Manchester Arena to various local hospitals, and also treated more than 60 people who were considered “walking wounded” at the scene.

Children, including young girls, are among the victims, according to reports. The first victim of the attack has been identified as 18-year-old Georgina Callandar. Two other victims have been identified as 8-year-old Saffie Rose Roussos and 26-year-old John Atkinson.

The Greater Manchester Police said on Twitter, “An emergency number is available for those who are concerned about loved ones or anyone who may have been in the area – 0161 856 9400.”

Here is what we know about Salman Abedi and the attack so far:

1. Abedi, Who Was Known to British Authorities, Is Believed to Have Traveled to Libya Recently, Where He Received Terror Training

Salman Abedi detonated an improvised explosive device as the concert was coming to a close, killing 22 people and wounding dozens more as Ariana Grande fans, including children, left the show. Authorities say it appears he timed the attack for when fans exited the building, for maximum damage, in an area just outside of the security perimeter.

Abedi’s ID was found at the scene and he was tracked by CCTV cameras, the New York Times reports. He is believed to have traveled from London to Manchester by train prior to the attack, Reuters reports.

Prime Minister Theresa May said the attacker tried to “maximize carnage and to kill and injure indiscriminately.”

Abedi was previously known to British authorities, CBS News reports. The Times of London reports he was known to security services because of a connection to fellow Manchester native Raphael Hostey, an Islamic State recruiter killed in 2016 in a drone strike in Syria.

Times reports Abedi "known to security services as an associate of Raphael Hostey". Rapper Hostey was prolific IS recruiter from Moss Side — Ross Kempsell (@rosskempsell) May 23, 2017

He is of Libyan descent, but was born in Britain, and has traveled to Libya several times, including within the past three weeks, the Times of London reports. A friend told the newspaper Abedi returned from his most recent trip just days ago.

According to The Sun, Abedi was trained by terrorists in Libya while making trips to visit relatives there. He may have also traveled to Syria, where he had connections through Housey, the newspaper reports.

“His potential ties to Syria now very much forms one line of inquiry,” a source told The Sun.

He also had possible ties to other Britons of Libyan descent who have been snared in terror probes, including brothers Abdalraouf and Mohammed Abdallah, The Telegraph reports. The 23-year-old Abdalraouf Abdallah was sentenced to more than five years in prison last year for helping jihadis join ISIS.

It is not clear if his connections led Abedi to meet directly with ISIS fighters, or if they helped him learn the skills necessary to carry out the attack. It is also not known how he learned to make the bomb he used.

The explosion occurred near the foyer area of the arena, British Transport Police told The Sun. Sources told the newspaper the explosion was a “nail bomb attack,” but police have not confirmed that detail.

NHS sources are saying the explosion at Manchester Arena was a nail bomb attack. Still unconfirmed. — Tom Newton Dunn (@tnewtondunn) May 22, 2017

According to ITV News security editor Rohit Kachroo, the wounds were consistent with shrapnel injuries and nuts and bolts were found at the scene.

NBC Newsis reporting that it was an attack carried out by a suicide bomber wearing a backpack bomb.

NBC News: UK authorities suspect a possible suicide bomber responsible for incident at Ariana Grande concert in Manchester sources say. — Tom Winter (@Tom_Winter) May 23, 2017

CBS News is reporting the bomber blew himself up at the arena. According to the CBS report, the bomber took the Tube to Victoria Station, went to the ticket area of the arena and detonated an explosive device as people left the concert. Investigators found ball bearings at the scene and have traced the bomber’s movements through CCTV cameras. The cameras recorded the moment he detonated the bomb.

Lauren Valentine Barrow, a local singer and concert booking agent, posted on Facebook, “I have heard from quite a few people that know staff from the arena saying that there were suicide bombers at the foyer entrance near McDonald’s. It’s not confirmed of course but all the things I am hearing are not good. I hope you are all safe.”

Early reports indicated equipment exploded, sparking a panic. There were also reports early on of multiple explosions, but many witnesses have since described hearing only one blast. Concertgoers were holding pink balloons handed out by Ariana Grande’s team as part of the concert, and popping balloons were possibly mistaken for gunshots.

Wtf is happening in Manchester arena? Massive bang & everyone is running & screaming, people are crying — Rebecca B (@RebeccaBx) May 22, 2017

“There were just a loud bang and a flash and everyone tried to scramble out. An alarm came on telling everyone to stay calm but leave as quickly as possible,” Jade Baynes, 18, of Hull, told The Guardian. Another witness, Oliver Jones, also gave a description to The Guardian of what he witnessed:

I was in the toilet and heard a loud bang just after the concert had finished and people had started to leave. The bang echoed around the foyer of the arena and people started to run. I seen people running and screaming towards one direction and then many were turning around to run back the other way. Security was running out as well as the fans and concert goers. Reports of blood and people injured. In so much shock and panic. You see this on the news all the time and never expect it to happen to you. I just had to run and make sure me and my sister were safe.

Another witness told the BBC she saw some people being injured in the stampede as people tried to exit after the blast.

“As we turned around the corner there was an horrific stampede of people coming down the steps, people falling on floor,” she told the news station. “I grabbed my daughter and we just ran. There were people being crushed on the floor.”

If you look towards the left you see the explosion and hear the bang. I hope to GOD everyone is ok, and so glad Jess and Em are. #manchester pic.twitter.com/q81KHGEJ6E — Joe Gregory (@JoeAaronGregory) May 22, 2017

A video posted to Twitter claims to show the moment the explosion occurred. The footage was recorded by a dashboard camera. After a few seconds a bright light can be seen near the building and a loud blast can be heard.

A second video showed people inside the arena as the blast was heard:

Another video showed the chaos outside:

Two loud bangs heard around Manchester arena. People running out of the arena. No idea what's going on pic.twitter.com/KaRzQckvEE — Alan Brennan (@alanbmufc92) May 22, 2017

A witness, Ivo Delgado, told CNN the incident occurred after the concert was ended and while people were beginning to leave. Delgado told the news network he heard a loud bang and saw a little bit of smoke, along with people on the floor who were injured. He said a lot of people were screaming, including many “little girls.”

EXPLOSION AT MANCHESTER ARENA AND EVERYONE RAN OUT SO SCARY? pic.twitter.com/pJbUBoELtE — ♡♡ (@hannawwh) May 22, 2017

Videos showed panic inside and outside of the Manchester Arena after the explosion. People went running, witnesses said.

Panicking at Victoria Station after @ArianaGrande concert. Hope everyone is all safe and well. pic.twitter.com/6Q5WNXFkFO — Zach Bruce (@Zach_bruce) May 22, 2017

People also spilled into Victoria Station, which is located at the arena.

You can watch other videos at the link below:

2. Abedi’s Parents Came to Britain as Refugees, but He Was Born in Manchester & Was Studying at Salford University

Salman Abedi, 22, named by police as suspected Manchester bomber, responsible for killing 22 people at a pop concert. @itvnews pic.twitter.com/fiU8qxaem1 — Peter A Smith (@PeterAdamSmith) May 23, 2017

Salman Abedi is of Libyan descent. His parents were born in Libya and came to Britain as refugees, The Telegraph reports. They were trying to escape the Gaddafi regime, the newspaper reports.

Abedi was born in Greater Manchester. He has two brothers and a sister, according to The Telegraph. The family has also lived in London, and he was raised in the Whalley Range area of Manchester. His family has lived Fallowfield area of south Manchester for about 10 years, according to the newspaper.

Abedi was a student at Salford University, the Manchester Evening News reports.

“All at the University of Salford are shocked and saddened by the events of last night. Our thoughts are with all those involved, their families and their friends,” Pro-Vice Chancellor of Student Experience, Sam Grogan, said in a statement. “We have provided, and continue to provide, support to all students and staff who have been affected.”

Grogan said there was an “unrelated incident” that led to three buildings being evacuated on Tuesday as a “precautionary measure for a short period of time.”

The Evening News reports that Abedi had been studying business administration at the university. He began taking classes there in 2014, but hadn’t gone recently. He did not live at the school and did not have any disciplinary issues there, authorities said.

Police were carrying out raids on several locations around Greater Manchester on Tuesday after the attack, including the home in Fallowfield where Abedi was registered as living with his family. Police used a controlled explosion to gain entry to the house.

Investigators searched the home of his brother, Ismael Abedi, in the Chorlton area of south Manchester, The Guardian reports. His brother was taken into custody, but it is not clear how, if at all, he is connected to the bombing.

His younger brother, Hashem Abedi, was also take into custody in Tripoli.

Hashem Abedi, younger brother of the Arena suicide Bomber Salam Abedi, has been arrested in Tripoli. pic.twitter.com/h5lPcY7yRc — BBC North West (@BBCNWT) May 24, 2017

His father was later detained as well.

the father of #Manchester suicide bomber was doing TV intv when two cars full of gunmen took him from his house in #Tripoli . eyewitness — Lutfi Abu Aun (@lutfiabuaun) May 24, 2017

A neighbor told the New York Times the family was quiet and they knew little about them. They sometimes flew a Libyan flag outside their home.

“They didn’t really speak to anyone,” Lina Ahmed told the Times. “They were nice people if you walked past.”

Those in the Manchester Libyan community were shocked to learn Abedi was the bomber.

“Salman? I’m astonished by this,” one person told the Guardian. “He was such a quiet boy, always very respectful towards me. His brother Ismael is outgoing, but Salman was very quiet. He is such an unlikely person to have done this.”

A schoolmate had a different take.

“I saw him last year and he had a beard thing going on. We didn’t speak but just nodded to each other. I don’t remember seeing him with beard before. He always had a bit of an attitude problem. I can’t say I really liked the man,” Leon Hall told the Daily Mail.

According to The Guardian, Abedi and his family worshipped at Didsbury mosque in Manchester. His father, Abu Ismael Abedi, is a well-known figure in the community.

“Abu Ismael will be terribly distraught,” one community member told the newspaper. “He was always very confrontational with jihadi ideology, and this Isis thing isn’t even jihad, it’s criminality. The family will be devastated.”

His father is believed to be in Tripoli, while his mother, Samia, is thought to be in Manchester, neighbors told the newspaper. According to The Guardian, Abu Ismael Abedi has traveled back and forth between Tripoli, as has Salman Abedi.

“I can’t believe he would have been radicalised in Tripoli. All those types have been driven out of the city. It must have happened here,” the neighbor said. “But what was he doing, murdering all those people. There must have been somebody influencing him. It’s terrible. He was off his head.”

3. Police Do Not Believe Abedi Was Working Alone & He May Have Been a ‘Mule’ Carrying

a Bomb Made by Someone Else

Armed polices just pulled a man out of a car and arrested him pic.twitter.com/nQF37PfjHF — Tas (@DrNinja_) May 22, 2017

Police do not believe Salman Abedi was working alone. Several arrests have been made during raids around Greater Manchester in the two days after the bombing. Police are working to determine who was part of the plot and if they were working with a terror group, like ISIS.

According to the Manchester Evening News, police believe Abedi was possibly a “mule” carrying a bomb built by someone else. Police do not believe they have the bombmaker in custody. The country’s terror threat level has been raised to critical, with Prime Minister Theresa May telling the nation that means another attack could be imminent.

Big arrest of two men by masked police happened right now in Salford! Scary #manchester #PrayForManchester pic.twitter.com/R1XSEJnwNF — Ella Glaesener (@G11GGSY) May 24, 2017

A spokesman for the Greater Manchester Police said Tuesday that they are working to investigate if the attacker, Abedi, was connected to a larger network or was working alone.

“We are currently treating this as a terrorist incident until we know otherwise. We are working closely with the national counter terrorism policing network and UK intelligence partners,” Chief Constable Ian Hopkins said in a statement. “This is clearly a concerning time for people but we are doing all we can working with local and national agencies to support those affected and gather information about what has happened tonight. As you will understand we are still receiving information and updates so will provide more details when we have a clearer picture.”

Hopkins added,” I want to thank people for their support and would ask them to remain vigilant and if they have any concerns report them in confidence to us on the Anti-Terrorist Hotline 0800 789321. It is important people avoid the area so that we can effectively deal with the incident.”

The incident comes after raids on terror groups in London that led to at least four arrests, The Guardian reported on May 17. Police said the four men were arrested on “suspicion of being concerned in the commission, preparation or instigation of acts of terrorism.” Met Police said, ” These arrests were pre-planned as part of an ongoing investigation by the Met’s counter-terrorism command and MI5. The arrests are linked to activity in the UK.” Police also carried out raids in late April, leading to arrests that they say disrupted two separate attack plots, including one man arrested in Westminster and another in north west London, where a woman was shot and subsequently charged criminally along with two other women.

“There is a complex and wide ranging investigation underway. Our priority is to work with the National Counter Terrorist Policing Network and UK intelligence services to establish more details about the individual who carried out this attack,” Greater Manchester Police Chief Constable Ian Hopkins said.

“We have received tremendous support from across the police services and partner agencies throughout the night,” Hopkins said. “We regularly carry out exercises to test our ability ro respond to such incidents and this has ensured a very swift response from local and national agencies.”

Hopkins said a large cordon remains in place around Manchester Arena and the Victoria Train Station, which will be in place for some time.

“Terrorists attempt to disrupt our lives and create distrust and fear in communities,” Hopkins said. “We have a long history in Greater Manchester of communities standing together during difficult times. In the coming days we will be working closely with community leaders to address any issues. It is important that we all continue to remain vigilant, but also to go about our daily lives.”

Hopkins added, “As people are waking up to this tragic news on what is a sad day for Greater Manchester, the officers and staff from Greater Manchester Police and the other emergency services will continue to do all they can to help get us through the difficult days ahead.”

4. ISIS Has Called Abedi a ‘Soldier’ After Its Supporters Celebrate the Attack on Social Media

1) No claim regarding blast in #Manchester, but #ISIS accounts celebrating the attack, disseminating media & threats pic.twitter.com/Z8VqKWUkXD — Rita Katz (@Rita_Katz) May 23, 2017

ISIS supporters immediately began celebrating the attack on social media, and the group officially claimed responsibility on Tuesday through its Amaq News Agency, according to the SITE Intelligence Group.

“With Allah’s grace and support, a soldier of Khilafah managed to place explosive devices in the midst of the gatherings of the Crusaders in the British city of Manchester, in revenge for Allah’s religion, in an endeavor to terrorize the mushirkin and in response to their transgressions against the lands of the Muslims,” the statement said. “The explosive devices were detonated in the shameless concert arena, resulting in 30 Crusaders being killed and 70 others being wounded. And what comes next will be more severe on the worshipers of the Cross and their allies, by Allah’s permission. And all praises is due to Allah, Lord of the creation.”

The statement called him a soldier of the Khilafah, or caliphate. It also says the attack was meant to terrorize the “mushirkin,” which means pagans or those who worship a false idol.

According to CBS News, experts are somewhat skeptical of ISIS’ claim of responsibility, saying the details of the statement do not match up with the actual events. The ISIS statement says multiple devices were detonated, while officials say there was only one explosion, among other inconsistencies, including the number of victims. ISIS has at times claimed an attack when it had no direct role in the planning and execution of it, but did influence a supporter to kill on its behalf.

U.S. Director of National Intelligence Dan Coats, who was already scheduled to testify before Congress on Tuesday, said, “”ISIS has claimed responsibility for the attack in Manchester…we have not verified yet the connection.”

"ISIS has claimed responsibility for the attack in Manchester…we have not verified yet the connection," Coats says https://t.co/T5uqoA85rO pic.twitter.com/4pA2ZmjxAF — CBS News (@CBSNews) May 23, 2017

Rukmini Callimachi, New York Times reporter who covers ISIS and is a leading expert on the group, tweeted, “So far officials indicated that the attack was likely carried out by a single suicide bomber. Claim suggests it was devices left behind … The chain of custody of this claim and its release on Telegram via Nashir, it’s timing and language is all in keeping with past claims. … What’s not divulged is whether ISIS had contact with the attacker. Remember ISIS considers inspired attacks to be part of core strategy.”

Unlike in some cases where the attacker had contact with ISIS, the statement did not mention the name of the bomber.

The U.K. terror alert was at “severe” before the explosion. The incident comes after an attacker inspired by the ISIS terror group drove a car into pedestrians on the Westminster Bridge in London, killing four people and injuring more than 50, before crashing his car into the fence of the British Parliament and fatally stabbing a police officer. The terrorist, Khalid Masood, was then shot dead by another officer.

The explosion also comes on the fourth anniversary of the death of a British Army soldier, Fusilier Lee Rigby, who was publicly executed by Islamic terrorists.

On Monday, before the claim of responsibility, Rita Katz, director of the SITE Intelligence Group, tweeted, “No claim regarding blasting in Manchester, but ISIS accounts celebrating the attack, disseminating media and threats.”

ISIS supporters often celebrate attacks and incidents that injure multiple people in the West, but that does not always mean the terror group is behind the incident. In several cases, ISIS supporters who have carried out attacks have been claimed by the group as its “soldier,” while no evidence of any direct contact between the terror group and the supporter can be found. ISIS has called for attacks on concert venues, like its coordinated assault on the Bataclan, and has tried to inspire homegrown terrorists in the West, including in Britain.

On Monday, also before the ISIS claim, Callimachi said, “Since news of the blast, I have been scouring both ISIS and al-Qaeda channels. Neither group has taken responsibility. … It’s at times like these that it’s important to remind ourselves there is a difference between official ISIS channels & unofficial ones.”

4. For ISIS – which once again has *not* claimed this heinous act – the official channels include Amaq & Nashir. See Amaq's logo below: pic.twitter.com/9r9aiQ2FEk — Rukmini Callimachi (@rcallimachi) May 23, 2017

5. It's on official channels that claims are posted. Beyond these there are 100s of unofficial pro-ISIS channels. This is the peanut gallery pic.twitter.com/lkGrt7kNxT — Rukmini Callimachi (@rcallimachi) May 23, 2017

6. Whereas official channels have generally been disciplined, only claiming attacks group inspired, peanut gallery is all over the place pic.twitter.com/td2pBqIgc8 — Rukmini Callimachi (@rcallimachi) May 23, 2017

7. This is all to say that if you trusted the peanut gallery (I don't) you'd be sure ISIS bombed Manchester. They're owning the horror: pic.twitter.com/iRN7IZk7H2 — Rukmini Callimachi (@rcallimachi) May 23, 2017

8. Across dozens of pro-ISIS channels, we're seeing celebration of this atrocity. They are hashtagging it #مانشستر which means #Manchester pic.twitter.com/wahcDViExK — Rukmini Callimachi (@rcallimachi) May 23, 2017

Here are some other experts reactions to the chatter related to the attack:

2) Pro-#ISIS forum users call #Manchester attack “a successful and surprising blow,” to #Britain, frame attack as retaliation for airstrikes pic.twitter.com/aDu1KBHaCE — Rita Katz (@Rita_Katz) May 23, 2017

3)Lately pro-#ISIS accounts have called supporters to"hunt your prey" in #UK providing info on community centers,tourist areas&gov buildings pic.twitter.com/wFkuuxsBFW — Rita Katz (@Rita_Katz) May 23, 2017

Key Islamic State-linked Telegram channels that have celebrated #Manchester attack now spreading words re Pound loss relative to Dollar pic.twitter.com/3IX3rcw7d5 — Michael S. Smith II (@MichaelSSmithII) May 23, 2017

INDICATOR Managers of Islamic State's English-language Khilafah News Telegram channels are ramping up posts at odd hours tonight #Manchester pic.twitter.com/QKAbnZFmja — Michael S. Smith II (@MichaelSSmithII) May 23, 2017

BREAKING Key Islamic State-linked Telegram channel now touting initial official statement re ostensible terrorist attack in #Manchester pic.twitter.com/qcykl92wFo — Michael S. Smith II (@MichaelSSmithII) May 23, 2017

ISIS related telegram channels seizing upon Manchester blast on Telegram but their chatter indicates they are watching coverage — Chris Sampson (@TAPSTRIMEDIA) May 23, 2017

U.S. President Donald Trump, who is traveling in Israel, has been briefed, a senior White House official told NBC News. The NYPD, FBI and other law enforcement have said they are taking precautions in the United States as a result of the Manchester incident.

5. Prime Minister Theresa May Called the Attack by Abedi ‘Callous’ & ‘Cowardly’

Prime Minister Theresa May, speaking to the country after a meeting Tuesday morning, called the attack “callous” and “cowardly.”

May said, “It is now beyond doubt that the people of Manchester and of this country have fallen victim to a callous terrorist attack – an attack that targeted some of the youngest people in our society with cold calculation.We struggle to comprehend the warped and twisted mind that sees a room packed with young children not a scene to cherish but as an opportunity for carnage.”

In a statement, Greater Manchester Mayor Andy Burnham said it is “our darkest of nights.”

“Manchester is today waking up to the most difficult of dawns. It is hard to believe what has happened here in the last few hours and to put into words the shock, anger and hurt that we feel today,” Burnham said. “These were children, young people and their families that those responsible chose to terrorize and kill. This was an evil act.”

U.S. President Donald Trump spoke while on a trip to Israel, saying, “So many young, beautiful, innocent people living and enjoying their lives murdered by evil losers in life. I won’t call them monsters because they would like that term, they would think that’s a great name. I will call them losers because that’s what they are. They’re losers. And we’ll have more of them. But they’re losers, just remember that.”

The arena is located in Hunts Bank, Manchester, immediately north of the center of the city, according to its website. The building was opened in 1995 and is one of the busiest indoor arenas in the world, hosting concerts and sporting events, including boxing and swimming.

It is managed by SMG Europe. The arena’s management has not yet released a statement about the incident. In a statement, Manchester Arena said, “We can confirm there was an incident as peopel were leaving the Ariana Grande show last night. The incident took place outside the venue in a public space. Our thoughts and prayers go out to the victims.”

“Since opening in 1995, the Arena has hosted the biggest names in live entertainment including U2, The Rolling Stones, Madonna, Lady Gaga, Pavarotti and the record-breaking 2010/2011 residency by local comedian Peter Kay,” the arena’s website says. “Manchester Arena has also played a key part in the city’s rich musical heritage with historic shows by local bands Take That, Oasis, Elbow, New Order, James, Happy Mondays, The Charlatans, Noel Gallagher’s High Flying Birds, M People, Doves, Inspiral Carpets, The Verve, Simply Red and The Courteeners. Attracting over one million visitors each year, the 21,000 capacity Arena is a former winner of the industry’s prestigious International Venue of the Year award.”

Manchester is located in the North West area of England. It is home to about 500,000 people, and is part of the second-largest urban area in the United Kingdom, with 2.55 million people living in the Greater Manchester area.

Pat Carney, a council spokesman for the Manchester city center, told the BBC, “It’s a very easy target – a concert hall where young people are enjoying music. The public are really co-operating by staying away from what is basically now a crime site. The world we live in, police and the council have emergency procedures that we practise all the time. Obviously everyone in the city is shocked, having seen how young some of these people are. The police are treating it as a live site, we don’t know if this is the end or there are other incidents in that area… we don’t know at the moment.”

Ariana Grande and her band were not injured in the incident, according to a statement from her representative.

“Ariana is okay,” a representative told Billboard. They said the are looking into what happened and have not commented further.

BIA, the supporting act for the concert, tweeted that she and her team are also “okay.”

Grande, 23, is on an international tour for her latest album, “Dangerous Woman,” and was set to perform shows in London on May 25 and 26. But TMZ reports her tour has been suspended indefinitely. TMZ also reports Grande is “inconsolable” and “in hysterics” after the bombing.

“We mourn the lives of children and loved ones taken by this cowardly act,” her manager, Scooter Braun, said in a statement. “We ask all of you to hold the victims, their families, and all those affected in your hearts and prayers.”

A large police presence could be seen outside the arena.

“Please AVOID the area as first responders work tirelessly at the scene,” Greater Manchester Police said.

People are still emerging, shell shocked: a family from Pontefract say they saw a woman stagger out, on open wound exposed all down one leg — Helen Pidd (@helenpidd) May 22, 2017

Wounded people could be seen leaving the arena, according to reporters.

“We’ve had a few people in with panic attacks and in all kinds of disarray. We’ve got four girls here – trying to get them sorted to get picked up. There was a gentleman on the floor with his leg all bleeding and woman with blood down one side of her face,” tyler, a bartender at the Steven Charles Snooker Club, told The Guardian. “We felt something but didn’t know what it was – there was a sound like thunder. One girl had a panic attack and another had streaming tears, a woman had a heart attack just outside.”

Armed police and helicopters overhead in Manchester, around the corner from the arena. All roads into town blocked off. pic.twitter.com/KMxniNNC3c — Frances Perraudin (@fperraudin) May 22, 2017

Ambulances were streaming to the scene and helicopters could be seen above.

Bomb disposal going into the arena. pic.twitter.com/FG3g4CkpoM — Frances Perraudin (@fperraudin) May 22, 2017

A bomb disposal unit could be seen going into the arena. And a controlled explosion was carried out several hours after the incident because of a suspicious package:

The controlled explosion on BBC News pic.twitter.com/or3fQd5ODJ — ~ (@afterglowlovato) May 23, 2017

The local ambulance service told The Guardian people should only call for “life-threatening emergencies,” adding that there has been a “large number of resources” directed to the incident already.

The U.S. Embassy in London issued a statement about the incident:

The U.S. Embassy in London informs U.S. citizens that there has been an incident at Manchester Arena. Emergency services are currently responding to reports of an explosion at the arena. U.S. citizens should heed guidance from local authorities and maintain security awareness. View updates from the Greater Manchester Police on Facebook @GtrManchesterPolice or on Twitter @GMPolice. Please monitor media and local information sources and factor updated information into personal travel plans and activities. We strongly encourage U.S. citizens in the United Kingdom to directly contact concerned family members in the United States to advise them of your safety.

You can find more information from the Embassy here.

The U.S. Department of Homeland Security said Monday night there is no specific credible threat to U.S. arenas or concert venues.

“We are working with our foreign counterparts to obtain additional information about the cause of the reported explosion as well as the extent of injuries and fatalities,” the U.S. Department of Homeland Security said in a statement Monday night. “U.S. citizens in the area should heed direction from local authorities and maintain security awareness. We encourage any affected U.S. citizens who need assistance to contact the U.S. Embassy in London and follow Department of State guidance.”

DHS also said it is ready to help its counterparts in the U.K. in their investigation.