Three foreign nationals carried out this week's attack on Istanbul's Ataturk international airport, killing 44 people in what appeared to be a coordinated strike on a major global transit hub, a Turkish official confirmed Thursday.
The three attackers came from Uzbekistan, Kyrgyzstan and Russia, he said. The Dogan news agency reported the Russian national was from the restive Caucasus region of Dagestan in the south of the country.
All three areas are predominately Muslim and were once part of the Soviet Union. A large number of radicalized people from the Caucasus and Central Asia have joined the Islamic State extremist group in Syria and Iraq.
No group has claimed the attack, which involved firearms and explosives, but Turkish officials are pointing the finger at Islamic State, which has been blamed for a number of attacks in the country during the past year.
The government confirmed that the attackers arrived at the airport by taxi. Hurriyet newspaper cited sources as saying the taxi driver told authorities the assailants spoke a foreign language.
Turkish Interior Minister Efkan Ala said there are 19 foreign nationals among the dead, the Anadolu news agency reported.
The deceased foreigners mostly hail from Arab and Central Asian nations and Afghanistan. Additionally, at least 23 Turks died. Most of the dead were Muslims.
Police arrested 13 people in raids against Islamic State at 16 locations in Istanbul, an official said, adding that separate operations netted nine people in Izmir province. It remained unclear if those people had links to the airport attack.
More than 230 people were hurt in the attack on Tuesday evening, the governor's office said, which saw the three assailants storm the building, killing themselves during the operation.
Two of the bombings - including the first, near a security checkpoint - appeared to have been focused on the arrivals terminal. Another attacker blew himself up in the departures area one level up, officials said.
One witness in the baggage claim area described seeing a "fireball" as the third explosion went off and panic and chaos took over.
Flights were disrupted in the hours after the attack, but the airport, one of the largest in the region, has mostly returned to normal operations.
Turkish President Recep Tayyip Erdogan said there was a "place in hell" for the attackers and vowed to fight against terrorism.
Tuesday's attack was the worst in Istanbul in more than a decade, as Turkey, a NATO member, struggles with a fresh wave of unrest.
Islamic State, which controls territory in neighbouring Syria, has been blamed for a number of attacks in Turkey during the past year. Although it has never claimed responsibility for a large-scale assault within Turkey, it has taken responsibility for assassinating Syrian activists in the country.
Turkey, a staunch backer of rebel groups fighting Syrian President Bashar al-Assad, was accused for years of having a porous border with the neighbouring country. Extremists were widely reported to have taken advantage of that border to get into Syria and join hardline Islamic factions fighting in the civil war.
Turkish security forces on Thursday also reported that they had shot dead two Syrians trying to cross into Turkey on Saturday. One was identified by Turkish intelligence as a potential suicide bomber planning an attack in either Ankara or Adana.
Turkey is also facing violence in the south-east, where state forces are battling Kurdish militants after a ceasefire broke down last year following stalled peace talks.