Turkish police were yesterday hunting an unidentified gunman who shot 39 people dead and left scores wounded at a nightclub.
Dozens of foreign nationals celebrating the start of the new year in Istanbul were among the victims of the shooting spree, at the Reina club, one of the city's most famous venues.
Wearing a Santa hat and armed with a long-barrelled weapon, the attacker shot a police officer before storming the elite club in the Ortakoy district of the city at about 1.45am.
The attacker left his gun before "taking advantage of the chaos" and fleeing the scene, Binali Yildirim, Turkey's prime minister, said.
President Recep Tayyip Erdogan condemned the attack, which left 69 wounded, and offered condolences for those who lost their lives, including "foreign guests".
The 24 foreign victims included seven people from Saudi Arabia, two Indians, two Tunisians, and one each from Canada, Syria, Lebanon, Belgium and Israel, the Turkish daily 'Hurriyet' reported. No group has claimed responsibility for the attack.
The Israeli victim was 19-year-old Leanne Nasser, who was visiting Istanbul with three friends. "Shots were fired from all directions and I saw dead and wounded people falling near me," one of Ms Nasser's friends, Alaa Abd al-Hai, told Israeli newspaper 'Haaretz'.
"I hid in some corner and didn't know what to do. Everyone was screaming and crying and the shooting didn't stop, it sounded like an eternity."
Some customers jumped into the waters of the Bosporus to escape.
Turkey has endured a series of major attacks in the past year, carried out by either Kurdish militants or Isil.
The jihadist group has repeatedly called for attacks on Turkey, most recently last month. In August, Ankara sent tanks and special forces into Syria to clear its border territory of Isil control.
Turkish authorities were last night starting to uncover evidence about the attack, but there was no clarity yet on who was responsible, Mr Yildirim said.
"Some details have started emerging, but the authorities are working towards a concrete result," Mr Yildirim told reporters when asked about who might have been behind the attack.
"Police and security officials will share information as it becomes available during the investigation," he said.
"Unfortunately (the gunman) rained bullets in a very cruel and merciless way on innocent people who were there to celebrate the New Year and have fun," Istanbul governor Vasip Sahin said, describing the carnage as a "terror attack".
CCTV footage appeared to show that the assailant wore a Santa Claus hat for part of the attack. The footage shows the male assailant dressed in black and carrying a backpack as he shoots down a police officer outside the Reina nightclub.
Footage taken by a different camera shows him inside the club wearing different clothes and a Santa Claus hat.
Reina owner Mehmet Kocarslan said police had boosted security measures in Ortakoy and its vicinity. The measures included tents at key locations with a 24-hour police presence and support from the Turkish Coast Guard.
"Despite all these precautions by police forces, unfortunately this painful event took place. We don't know what to say," he said. "We are at the point where all words end."
Turkish interior minister Suleyman Soylu said the gunman was still at large.