Three terrorists armed with bombs and guns attacked Istanbul Ataturk Airport, Europe’s third busiest airport, killing at least 36 people and injuring 147 on Monday evening (Istanbul time). The bombing is the fourth terrorist attack in Turkey this year.

In a scene reminiscent of the terror attacks at Brussels Airport witnesses described deadly carnage and crowds in a panic as the attackers struck. Video from inside the airport terminal shows people racing away as fast as they could and the bright orange flash from one of the explosions.

Another video shows a man walking with a gun, which he drops when he apparently is shot by a security officer. The man slumps to the ground and the officer briefly stands over him before running. About 10 seconds later, there is an explosion as he apparently detonates a suicide vest.

Of the three bombers in the Istanbul airport attack, two of them were at the international terminal, and the third terrorist was in the nearby parking lot, a Turkish official told CNN. All three detonated suicide vests.

Turkish President Recep Tayyip Erdogan called for a unified international fight against terrorism, saying: “Make no mistake: For terrorist organisations, there is no difference between Istanbul and London, Ankara and Berlin, Izmir and Chicago or Antalya and Rome. Unless all governments and the entire mankind join forces in the fight against terrorism, much worse things than what we fear to imagine today will come true.”

The airport was closed overnight for several hours, and flights into the airport had been diverted to the capital of Ankara and other cities. The airport has since reopened, and the US Federal Aviation Administration said it has lifted a ground stop for flights between the United States and the airport.

No group has claimed responsibility but early thinking is that it was ISIS or an ISIS-inspired group. Turkish officials said there is much more investigating to be done.