A US official says the organiser of the Istanbul airport massacre is a well-known terrorist who served as a top soldier in the ISIS war ministry.
Chairman of the House Committee on Homeland Security Michael McCaul said Akhmed Chatayev, from Russia's North Caucasus region, directed the three suicide bombers who killed 43 people Tuesday.
Turkish media reported that a man nicknamed "Akhmed One-Arm" organized the attack.
McCaul said while his whereabouts are unclear, his ties to jihadist activities are well documented.
At least 230 others were injured when the trio stormed Istanbul's Ataturk Airport and opened fire with rifles before detonating bombs. Two of the men targeted the international terminal building, and the third one gunned down people at the parking lot. Of the hundreds wounded, 80 are still hospitalized.
Last year, the U.S. Treasury added Chatayev to its list of terrorists, saying he was planning attacks against U.S. and Turkish facilities.
The United Nations has said he directly commands 130 militants.
Officials believe the three attackers are from Russia, Uzbekistan and Kyrgyzstan, and entered Turkey a month ago from Syria's ISIS stronghold of Raqqa.
They brought with them suicide vests, bombs and a deadly plan from ISIS leadership.