The gunman shot his way into Istanbul’s upscale Reina nightclub at around 1:15 am local time (22:15 GMT), just over an hour into the new year, killing a police officer and a civilian as he entered before opening fire at random inside.

Some witnesses said the gunman was dressed in a Santa Claus costume. Others spoke of multiple attackers, but officials have not confirmed this.

Turkish Interior Minister Suleyman Soylu said that at least 16 foreigners were among 39 people killed in the attack. Another 69 people are being treated in hospital for their wounds.

Indicating that the attacker was still at large, Soylu said: “The search for the terrorist contines.”

stanbul Governor Vasip Sahin said the attacker had used a “long-range weapon” to “brutally and savagely” fire on people.

The attack again shook Turkey as it tries to recover from a failed July coup and a series of deadly bombings in cities including Istanbul and the capital Ankara, some blamed on the Islamic State (IS) group and others claimed by Kurdish militants.

Attack targets New Year’s eve revellers

The club, one of Istanbul’s most iconic, popular with locals and foreigners alike, overlooks the Bosphorus Strait separating Europe and Asia in the city’s cosmopolitan Ortakoy district.

Around 500 to 600 people were thought to have been inside when the gunman opened fire. Some jumped into the waters of the Bosphorus to save themselves and were rescued by police.

US President Barack Obama, on vacation in Hawaii, expressed condolences and directed his team to offer help to the Turkish authorities, the White House said.

Governor Sahin and the interior minister said there was only one attacker but other reports, including on social media, suggested there may have been at least two, dressed in Santa Claus costumes which they later ditched.

The Hurriyet newspaper cited witnesses as saying there were multiple attackers and that they shouted in Arabic.

“We were having fun. All of a sudden people started to run. My husband said don’t be afraid, and he jumped on me. People ran over me. My husband was hit in three places,” one club-goer, Sinem Uyanik, told the newspaper.

“I managed to push through and get out, it was terrible,” she said, describing seeing people soaked in blood and adding that there appeared to have been at least two gunmen.

‘Police moved in quickly’

Dozens of ambulances and police vehicles were dispatched to the club in Ortakoy, a neighbourhood on the city’s European side nestled under one of three bridges crossing the Bosphorus and home to nightclubs, restaurants and art galleries.

“I didn’t see who was shooting but heard the gun shots and people fled. Police moved in quickly,” Sefa Boydas, a Turkish soccer player, wrote on Twitter.

“My girlfriend was wearing high heels. I lifted her and carried her out on my back,” he said.

Hurriyet quoted Reina’s owner, Mehmet Kocarslan, as saying security measures had been taken over the past 10 days after US intelligence reports suggested a possible attack.

When a lone gunman murdered dozens of New Year’s revelers early Sunday, he targeted a symbol of a cosmopolitan Istanbul that is increasingly under threat: a dazzling nightclub where people from around the world could party together, free from the mayhem and violence gripping the region.

It was there, at the Reina nightclub on the Bosporus — a hot spot for soap opera stars and professional athletes, Turks and well-heeled tourists — that those hoping to move past a particularly troubled year died together.

The assault was the second in two weeks in Turkey, and it further exposed the fault lines in a country that is increasingly tearing apart amid terrorist attacks and political instability.

With the gunman still on the loose Sunday night and a nationwide manhunt underway, the killings brutally highlighted a dilemma for Turkey’s authoritarian president, Recep Tayyip Erdogan: Even though he has cracked down on opponents and put in place security measures to bring stability to his rattled country, the attacks keep mounting.

“I don’t know what to say,” said Zeynep Ozman, whose brother, Ali, was wounded in the attack. “I don’t want to say anything political, but this can’t be accepted as the new norm. Terrorism is everywhere now, and the government has no control. Something needs to be done. There is no life left in Istanbul.”

Turkey has been reeling for several years now, as it has been increasingly drawn into the Syrian civil war. By opening its borders to foreign fighters trying to reach Syria, critics say, it inadvertently supported the rise of the Islamic State, which is now carrying out attacks within Turkey. Then, in 2015, a stalled war with Kurdish militants was renewed, and this summer, Turkey suffered from an attempted coup.

The attack on Sunday morning — a strike on the Western, urbane face of Istanbul — is likely to further diminish Turkey’s democracy by giving Mr. Erdogan a freer hand to expand his crackdown on opponents, which accelerated after the coup attempt. It is also likely to erode the country’s economy, which has already suffered because of a decline in tourism and foreign investment.

“Nothing that the government is doing is helping make Turkey more secure,” said Asli Aydintasbas, a prominent Turkish writer and a fellow at the European Council on Foreign Relations. “The crackdown on domestic dissidents is further destabilizing the country, and when it is not destabilizing, it is increasing the dangerous polarization here.”

On Sunday, Mr. Erdogan vowed in a statement that the fight against terrorists would bring the country together.

“They are working to destroy our country’s morale and create chaos by deliberately targeting our nation’s peace and targeting civilians with these heinous attacks,” he said. “We will retain our coolheadedness as a nation, standing more closely together, and we will never give ground to such dirty games.”

As it had after other recent attacks, the government imposed a news blackout, saying news outlets should report only official statements.

ISIS claim responsibility for Istanbul nightclub atrocity as police hunt gunman who murdered 39 revellers in five-minute shooting spree