Attackers dressed in Santa Claus suits opened fire inside a packed Istanbul nightclub shortly after midnight on New Year’s Day, killing at least 35 people and wounding dozens more, Turkish officials said.
Gov. Vasip Sahin of Istanbul Province called it a terrorist attack.
The attack occurred about 1:15 a.m. at the nightclub, Reina, where as many as 600 people were celebrating the New Year, officials said.
Mr. Sahin said the attackers — initial reports said there had been as many as three — had fired on the police before heading inside the club.
“One person first kills the police officer outside, and then a civilian,” the governor said. “Inside, he rained bullets brutally, mercilessly over innocent people who were there just to celebrate the New Year and have fun.”
The club overlooks the Bosporus — which separates Europe and Asia — and some clubgoers jumped into the water in their panic over the attack.
— CNN Türk ENG (@CNNTURK_ENG) December 31, 2016
— NTV (@ntv) December 31, 2016
Mehmet Kocarslan, the owner, told the Hurriyet news site that there had been increased security measures for the past 10 days after American intelligence officials had warned about an attack. He said the attackers had used Kalashnikov rifles.
Television footage showed dozens of ambulances rushing to the scene and people fleeing, some walking with difficulty, arm in arm.
Hurriyet said three assailants in Santa costumes had opened fire at the security staff members at the gate and stormed in. NTV, a Turkish channel, said the police were still searching for the attackers.
On the European side of Istanbul, the neighborhood is an international travel destination known for its food stalls and vibrant night life. The area is a mix of stone, brick and wooden buildings along pedestrian lanes.
Turkey is still recovering from a failed coup attempt that began on July 15 in which at least 265 people were killed.
Though the effort sputtered in a matter of hours, President Recep Tayyip Erdogan responded with a sweeping, months long crackdown targeting dissidents across Turkish society. In addition to arresting thousands of military personnel suspected of involvement in the coup, hundreds of thousands of civil servants, educational workers and journalists have been purged.
The coup and the assassination of the Russian Ambassador Andrey G. Karlov in Ankara on Dec. 19 raised concerns that the country’s security establishment has grown ineffective. The internal turmoil also raised doubts about how well Turkey will be able to participate in international counterterrorism efforts, especially with regard to the Islamic State.
In the wake of the crackdown, protests against Mr. Erdogan have led to frequent clashes between demonstrators and the police. And reports of targeted attacks against civilians after martial law was declared in July have revived painful memories of the political violence Turkey experienced in the 1970s and 1980s.