Explosions were reported along with gunfire at the airport on Tuesday. At least 36 people have been confirmed dead, according to the Istanbul governor, with at least another 147 injured. Prime Minister Binali Yildirim has also confirmed that there were three attackers, with all three opening fire before blowing themselves up.
According to Turkish authorities, the attackers opened fire with rifles before passing through the x-ray security checkpoint. Police returned fire, and the attackers detonated explosives.
Initial reports suggested that the attackers were armed with hand grenades, but the strength of the blasts suggests otherwise.
"According to information I have received, at the entrance to the Ataturk Airport international terminal a terrorist first opened fire with a Kalashnikov and then blew themself up," Turkish Justice Minister Bekir Bozdag told reporters.
While no terrorist group claimed responsibility initially, Dogan News Agency reports that Daesh, also known as IS/Islamic State, was claimed responsibility.
All flights at have reportedly been canceled until 8:00 am local time.
More than 61 million passengers traveled through the airport in 2015.
Turkey has seen a number of terrorist attacks in recent months. Two attacks in Istanbul earlier this year were claimed by Daesh, also known as IS/Islamic State, while a pair of car bombing in the capital of Ankara were claimed by a Kurdish militant group.