At least 34 were killed and more than 200 were wounded by a series of explosions that struck a Brussels airport and subway on Tuesday morning. ISIS has since claimed responsibility for the attacks.

Two explosions were heard at Brussels airport at about 8 A.M. local time. Approximately an hour-and-a-half later, an explosion was heard at the Maelbeek metro station, close to EU institutions. The explosions at the airport took place during the the busiest time there, and the blast at the metro occurred as a train arrived there during the morning rush hour.

Brussels fire officials said that a total of 212 people were wounded in the deadly attacks, 30 of whom were critically wounded by burns and 96 seriously wounded.

The French Ministry of Foreign Affairs said that eight French citizens are among the wounded, three of whom critically. The U.K. Foreign Office said two British nationals have been injured. According to NBC News, nine Americans were wounded in the attacks.

Israel's Foreign Ministry spokesman, Emmanuel Nahshon, said one Israeli was lightly wounded at the airport.

Open gallery view In a photo provided by the Belgian Federal Police, a man is shown who is suspected of taking part in the attacks at Belgium's Zaventem Airport and is being sought by police, March 22, 2016. Credit: AP

Prime Minister Benjamin Netanyahu spoke on the phone with Belgian Charles Michel on Tuesday evening, and offered condolences on behalf of the people of Israel and wished the wounded a speedy recovery.

Netanyahu told Michel that terror does not distinguish between countries and offered Israel's help and cooperation in the fight against terror.

The two prime ministers agreed to meet soon.

Israeli president Reuven Rivlin sent a condolence letter to King Philippe of Belgium in response to the attacks, saying that "the people of Israel share with me in mourning the sad loss of life."

"Terrorism is terrorism is terrorism, whether it takes place in Brussels, Paris, Istanbul or Jerusalem," the letter said. "I want to emphasize that this struggle that we all share, is against this violent terrorism that continues to kill and maim so many, it is not a fight against Islam."

Belgian security forces were said to have found a Kalashnikov assault rifle next to the dead attacker and a discarded bomb belt at Brussels airport.

Later on Tuesday evening, Belgian police found an ISIS flag and a bomb while conducting a house search in the Brussels district of Schaebeek. Prime Minister Michel said police were carrying out raids following the attacks.

Brussels police have issued a wanted notice for a man suspected of involvement in the airport attack.

"A photograph of three male suspects was taken at Zaventem. Two of them seem to have committed suicide attacks. The third, wearing a light-colored jacket and a hat, is actively being sought," Federal prosecutor Frederic Van Leeuw told a news conference. A government official said later that the third suspect was seen running away from the airport building.

Federal prosecutors described the incidents as terror attacks that were carried out by suicide bombers – two at the airport and one in the subway. Eyewitnesses had told Belga news agency that they had heard shots and calls in Arabic before the explosions at the airport which, Sky News in London cited reports as saying, took place in the departures lounge near the American Airlines desk.

Eyewitness videos show distruction, chaos at Zaventem airport in Brussels.

An Iraqi intelligence official said sources in the Syrian city of Raqqa told them that ISIS has been planning terrorist attacks in Europe for two months which would "target airports and train stations."

The official told The Associated Press on Tuesday that Iraqi officials told European countries about the plans "but Brussels was not part of the plans" at the time.

He said ISIS militants changed the operation and moved it to Brussels "because of the detention of Salah Abdeslam" — the Paris attacks suspect arrested Friday in Brussels.

Open gallery view Broken windows seen at the scene of explosions at Zaventem airport near Brussels, Belgium, March 22, 2016. Credit: Reuters

Another senior Iraqi intelligence official said "Daesh (ISIS) was behind this operation and it was planned in Raqqa two months ago and there are three suicide attackers who will carry out another attack."

Supporters of Islamic State praised the blasts on social media. "The state will force you to reevaluate your ways a thousand times before you are emboldened to kill Muslims again, and know that Muslims now have a state to defend them," said one supporter of the group on Twitter.

In a statement, ISIS said there will be "black days" ahead in return for aggression against the militant group.

next previous 12 of 12 | Emergency personnel are seen at the scene of a blast outside a metro station in Brussels, in this still image taken from video on March 22, 2016. Credit: Reuters 1 of 12 | Broken windows seen at the scene of explosions at Zaventem airport near Brussels, Belgium, March 22, 2016. Credit: Reuters 2 of 12 | A truck carrying soldiers of the Belgian Army arrives after a explosion in a main metro station in Brussels on Tuesday, March 22, 2016. Credit: AP

Aiport, city on lockdown

The airport was shut down, with no flights departing or landing. The airport CEO said it will remain closed through Wednesday. Train traffic to the airport was also halted, Belga wrote. The Brussels transport authority said all Metro stations in the city were closing.

Passengers were evacuated, and video posted on social media showed people running out of the airport as smoke rose from the building.

Belgian public broadcaster VRT put the death toll from the twin attacks 34, with 20 people killed in the blast on a metro train and 14 in explosions at the airport.

The European Commission locked down its staff after the explosions, the vice president in charge of personnel tweeted. A spokesman for officials working in the European Parliament nearby said the legislature was working normally.

Maelbeek metro station, Brussles after an explosion there, March 22, 2016. Credit: Social Media

The U.S. Embassy urged citizens to take shelter and avoid public transport, Bloomberg reported. Meanwhile, a Belgian crisis center told people to "Stay where you are" and the state announced it would send 225 extra military troops to the capital.

A U.S. official said security officials believe at least one suitcase bomb was detonated at Brussels Airport on Tuesday morning. The official, who wasn't authorized to speak publicly on the early investigations, confirmed a statement by a Brussels official that there is also concrete evidence of one suicide bombing at the airport Tuesday.

Eyewitnesses described mayhem at the airport and subway.

Zach Mouzoun, who arrived on a flight from Geneva about 10 minutes before the first blast, told BFM television that the second, louder explosion brought down ceilings and ruptured pipes, mixing water with blood from victims.

"It was atrocious. The ceilings collapsed," he said. "There was blood everywhere, injured people, bags everywhere."

"We were walking in the debris. It was a war scene," he said.

Near the entrance to the Maelbeek subway station, not far from the headquarters of the European Union, rescue workers set up a makeshift treatment center in a local pub. Dazed and shocked morning travelers streamed from the metro entrances as police tried to set up a security cordon.

"The metro was leaving Maelbeek station for metro when there was a really loud explosion," said Alexandre Brans, 32, wiping blood from his face. "It was panic everywhere. There were a lot of people in the metro."

First responders ran through the street outside with two people on stretchers, their clothes badly torn.

A hospital official said that the bombs used in the airport attack contained nails and that victims are being treated for fractures, burns and deep cuts at a local hospital.

The explosions at the airport hit at the middle of the busiest time there. Smoke was seen billowing out of the terminal.

Amateur video shown on France's i-Tele television showed passengers including a child running with a backpack dashing out of the terminal in different directions as they tugged luggage, Another image showed a security officer patrolling inside a hall with blown-out paneling and what appeared to be ceiling insulation covering the floor.

"I knew it was an explosion because I've been around explosions before," said Denise Brandt, an American woman interviewed by Sky television.

"I felt the explosion, the way it feels through your body. And we just looked at each other and I said 'Let's go this way.' It was over there. There was just this instinct to get away from it. Then we saw people running, crying, toward us. So I knew we were going in the right direction and away from it."

With three runways in the shape of a "Z," the airport connects Europe's capital to 226 destinations around the world and handled nearly 23.5 million passengers in 2015.

Passengers were led onto the tarmac and the crisis center urged people not to come to the airport.

Belgium had been on high alert since the arrest in Brussels last week of Salah Abdeslam, a key suspect in the Paris terrorist attacks. After the airport explosions, the Interior Ministry raised the country's security alert to a maximum Level Four across the country, Belga reported.

Belgium's prime minister said there was no information now whether Tuesday's attacks were related to the Paris suspect's arrest.

President Barack Obama pledged that the U.S. will "do whatever is necessary" to help Belgium bring to justice the perpetrators of the terrorist attacks that hit Brussels.

He said the U.S. stands "in solidarity" with Belgium in condemning "these outrageous attacks against innocent people." He added that the attacks are another reminder that "the world must unite" against the "scourge of terrorism."

Amtrak, the U.S. railroad service, deployed extra officers to stations and trains throughout the country in response to the attacks.

Officials in Germany's North Rhine-Westphalia state announced tighter controls on the border with Belgium following the attacks.

The U.K. updated travel guidance to advice against all but essential travel to Brussels.