Attention turned Thursday to the identity of the three attackers at Istanbul's Ataturk international airport, who killed 42 people in what appeared to be a well-coordinated strike on the major global transit hub, involving firearms and explosives.
No group has claimed the attack, but Turkish officials are pointing the finger at the Islamic State extremist group, which has been blamed for a number of attacks over the past year in the country.
Hurriyet newspaper reported that one of the attackers was believed to be a Russian national, possibly from the restive Chechen region. A large number of radicalized people from the Caucasus have joined Islamic State in Syria and Iraq.
A Turkish official said they have not yet been able to identify the attackers, due to extensive damage to the bodies, but it is possible one was a foreign national.
Officials have confirmed the attackers arrived at the airport by regular taxi. Hurriyet cited sources as saying the taxi driver told authorities the assailants spoke a foreign language.
Turkish officials said on Wednesday that 23 of the dead are Turkish citizens and at least 13 are foreign nationals, including from Arab and Central Asian nations.
The Afghan government has since said four are its citizens while the Palestinians also confirmed one of their own died, as it became clearer that most of those killed were Muslims.
The state-run Anadolu news agency reported on raids against Islamic State at 16 locations in Istanbul. Police arrested 13 people, including three foreign nationals.
More than 230 people were hurt in the attack on Tuesday evening, 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 eyewitness 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, was blamed for a number of attacks in Turkey over the past year.
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, which was also utilized by extremists joining hardline Islamic factions fighting in the civil war.