ISTANBUL: Details are emerging about the three suicide bombers who carried out this week's deadly Istanbul airport attack and how they did so.
Here's what we know so far:
Who carried out the attack?
There has been no claim of responsibility for the attack, but Turkish officials say early evidence points to a strike by the Islamic State group.
The director of the CIA, John Brennan, also said the suicide assault bore the "hallmark" of the jihadist group.
Who were the suicide bombers?
A senior Turkish official said the three bombers were from Russia, Uzbekistan and Kyrgyzstan.
Central Asia's former Soviet republics are among the main countries of origin for foreign jihadists who have gone to fight in Iraq and Syria.
Up to 7,000 people have left Russia and the former Soviet republics to fight for IS, Russian President Vladimir Putin said in October.
The Hurriyet newspaper named one attacker as Osman Vadinov, saying he was from the Russian region of Chechnya and had arrived from the IS Syrian stronghold Raqa.
Kremlin spokesman Dmitry Peskov said however that Moscow was unaware that a Chechen had taken part in the triple bombing.
Russia's Interfax news agency, quoting a security source in the North Caucasus, said there was no record of an "Osman Vadinov" and that it was not a Chechen name.
Kyrgyzstan's foreign ministry also said consular officials in Istanbul met with Turkish anti-terror officials and they had not yet confirmed a Kyrgyz national was among the bombers.
Who's been arrested?
Turkish Interior Minister Efkan Ala said Thursday that 13 people had been arrested in connection with the Istanbul attack, including four foreigners.
Police had carried out a string of raids in several Istanbul districts early Thursday, including on IS safe houses.
How was the attack carried out?
The attackers arrived at Ataturk airport's international terminal by taxi before firing at passengers with automatic rifles and detonating suicide bombs at around 10:00 pm (1900 GMT) on Tuesday.
Prime Minister Binali Yildirim said they shot their way into the airport after realising they would not get through the security barriers at the entrance.
"The terrorists failed to pass through the regular security system, scanners and police control," he told reporters late Wednesday.
"They returned and came back with long-range rifles they took out from their suitcases, and passed the security control by opening fire randomly at people," he said.
"One of them blew himself up outside and the other two took advantage of the panic during the opening of the fire, entered inside and blew themselves up."
A senior source close to the presidency gave a slightly different account, saying two attackers blew themselves up on separate floors of the airport before the third followed suit outside.
Who were the victims?
State-run news agency Anadolu said 44 people had been killed. More than 200 people were injured and the interior minister said the dead included 19 foreigners.
They include three Saudis, a Chinese national, an Iranian, a Ukranian, and a Palestinian woman.
Two Iraqis, an Uzbek and a Jordanian were also among the dead.
A Tunisian doctor killed in the attack was in Turkey trying to secure the release of his son, who had been detained for joining IS, according to diplomats.
The Turkish victims included four members of the Amiri family -- three women and a nine-year-old girl, Huda, whose joint funeral was attended by hundreds in Istanbul on Thursday.
Living in Saudi Arabia, they were coming back for a holiday to mark the Muslim holy month of Ramadan when the bombers struck.