INSTANBUL (AP) - Turkish police are hunting for an assailant who -- reportedly dressed as Santa Claus -- opened fire at a crowded Istanbul nightclub during New Year's celebrations Sunday, killing at least 39 people and wounding close to 70 others in what authorities said was a terror attack.
The attacker, armed with a long-barreled weapon, killed a policeman and a civilian outside Istanbul's popular Reina club at around 1:15 a.m. before entering and firing on people partying inside, Gov. Vasip Sahin said. He did not say who may have carried out the attack.
Interior Minister Suleyman Soylu said the attacker, who has not been identified, was still at large. "Our security forces have started the necessary operations. God willing he will be caught in a short period of time," he said.
Private NTV news channel said the assailant entered the upscale nightclub, on the shores of the Bosporus, on the European side of the city, dressed in a Santa Claus outfit. The minister said the attacker was believed to have left the club wearing different clothing to what he entered the club in. He said the attacker is believed to have carried out the assault alone.
At least 15 of the dead were foreign nationals, Soylu said, without providing information on their nationalities. Five of the victims were identified as Turkish nationals while authorities were still trying to identify the rest. At least 69 people were being treated in hospitals, four in serious condition, Soylu said.
Three or four of the Turkish victims may have been employees at the nightclub, he said.
"This was a massacre, a truly inhuman savagery," Soylu said.
Gov. Sahin said: "Unfortunately (he) rained bullets in a very cruel and merciless way on innocent people who were there to celebrate New Year's and have fun," Sahin told reporters.
Some customers jumped into the waters of the Bosporus to escape the attack, the NTV report said.
Sinem Uyanik was inside the club with her husband, who was wounded in the attack.
"Before I could understand what was happening, my husband fell on top me," she saidoutside Istanbul's Sisli Etfal Hospital. "I had to lift several bodiesfrom on top of me before I could get out. It was frightening." Her husband was not in serious condition despite sustaining three wounds.
Police with riot gear and machine guns backed up by armored vehicles blocked the area close to the Reina nightclub, one of the most popular night spots in Istanbul. Several ambulances flashing blue lights arrived on the scene, some taking wounded to hospitals.
The White House condemned what it called a "horrific terrorist attack" and offered U.S. help to Turkey.
White House spokesman Eric Schultz said President Barack Obama was briefed on the attack by his national security team and asked to be updated as the situation developed. Obama is vacationing in Hawaii this week with his family.
European Union foreign policy chief Federica Mogherini tweeted: "Our thoughts are with victims and their loved ones. We continue to work to prevent these tragedies,"
The British ambassador to Turkey, Richard Moore, noting that foreigners were among the victims, urged British nationals in the city to let their families know they were safe.
An estimated 600 people were celebrating inside the club that is often frequented by famous locals, including singers, actors and sports stars. Several shocked revelers were seen fleeing the scene after the attack and the music fell silent.
Turkey was rocked by a series of deadly attacks in 2016 carried out by the Islamic State group or Kurdish militants, killing more than 180 people.
On Dec. 10, a double bomb attack outside a soccer stadium near the Reina nightclub killed 44 people and wounded 149 others. The attack was claimed by Turkey-based Kurdish militant group, the Kurdish Freedom Falcons. Nine days later, an off-duty Turkish riot policeman assassinated Russian Ambassador Andrei Karlov at a photo exhibition in the capital, Ankara. The government has suggested that a movement led by U.S.-based Muslim cleric Fethullah Gulen was behind the killing -- an accusation the cleric has denied.
Justice Minister Bekir Bozdag vowed that Turkey would press ahead with its fight against violent groups.
"Turkey will continue its determined and effective combat to root out terror," Bozdag said on Twitter.
Security measures had been heightened in major Turkish cities, with police barring traffic leading up to key squares in Istanbul and the capital Ankara. In Istanbul, 17,000 police officers were put on duty, some disguised as Santa Claus and others as street vendors, Turkey's Anadolu news agency reported.
Associated Press writers Mehmet Guzel in Istanbul and Suzan Fraser in Ankara, Turkey, contributed to this report.
This story has been corrected to give the time of the attack as 1:15 a.m., not 1:45.