UPDATE 3: Manchester police confirmed 19 are dead and around 50 injured. They received "reports of an explosion at Manchester Arena" just before 10:35pm local time. British Transportation Police report, "Officers are at Manchester Arena following reports of an explosion within the foyer area of the stadium at 10.30pm this evening." NBC reports that officials suspect a suicide bomber is to blame for the incident.

Latest statement on incident at Manchester Arena pic.twitter.com/BEpLOan3dY — G M Police (@gmpolice) May 23, 2017

UPDATE 2: Manchester's regional counter terrorism unit is treating this as a possible terrorist incident, according to the BBC's Daniel Sandford.

The North West Counter Terrorism Unit is treating the incident at #ManchesterArena as a possible terrorist incident. — Daniel Sandford (@BBCDanielS) May 22, 2017

UPDATE 1: Greater Manchester Police have issued a statement that there have been a number of confirmed fatalities and others injured at Manchester Arena. An on-the-ground source tells Billboard at least 18 have been reported dead.

Police statement on incident at Manchester Arena pic.twitter.com/gaKASukx9a — G M Police (@gmpolice) May 22, 2017

Emergency services have rushed to the U.K.'s Manchester Arena where Ariana Grande had been performing Monday (May 22) after concertgoers claim two explosions were heard.

Billboard has confirmed Grande is "okay" with the singer's rep and that her team is further investigating what happened. Supporting act BIA confirmed she and her team were also "okay."

So far no official report has been issued, but people at the concert and in the surrounding area are posting on social media that there were two bangs and people running out of the 21,000-person capacity arena.

CNN spoke to one of the concertgoers, Kiera Dawber, immediately after she exited the arena. Dawber said she saw "at least" 20 dead, and didn't think it looked like the deaths were the result of a stampede. "There was a massive explosion, a bang, smoke coming through the steps…It was just chaos."

Going through corridors to exit the arena, Dawber described seeing "at least 20, 30 people on the floor. Just… dead. You could see they were passed away, some people with injuries. There was a guy holding what looked like his wife and she wasn't in a good state….There was blood and shoes and handbags and bits of food and phones….I don't think I'll ever get rid of the images."

One man captured video of an emergency vehicle racing to the scene. See it here:

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

Others shared video from from the frightening scene inside the arena:

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

New video shows mass panic as fans flee Ariana Grande concert at the #Manchester Arena after 2 explosions.pic.twitter.com/gufS5r7tRj — Tennessee (@TEN_GOP) May 22, 2017

I was inside Ariana Grande's concert in Manchester Arena. Right at the end a explosion was heard. Smoke on the corridors and blood — Critico en serio (@criticoenserio) May 22, 2017

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

Network Rail has told Reuters U.K. and other outlets that all train lines out of the Manchester Victoria station are currently blocked with emergency services in attendance. Mancunians around the arena are offering to take in anyone stranded in the area with the hashtag #RoomforManchester on Twitter.

Local police are calling it a "serious incident" and asking people to stay away from the area.

Emergency services responding to serious incident at Manchester Arena. Avoid the area. More details will follow as soon as available — G M Police (@gmpolice) May 22, 2017

Greater Manchester is the United Kingdom's second-most populous urban area with a population of 2.55 million.

We will update as more details become available.