Istanbul (CNN) At least 39 people were killed and at least 69 wounded in an attack in a nightclub early Sunday as they were celebrating the new year, Turkey's Interior Minister said.

"We are face to face with a terror attack," Interior minister Suleyman Soylu told reporters.

Twenty-one of the dead have been identified, he said. Of those, 16 were foreign nationals and five were Turkish.

US officials also called it a terrorist attack, making it the first of 2017.

Latest developments

The death toll from the Reina nightclub shooting has risen to 39

The number of injured is at 69; "Four of them are in critical condition -- one very critical," says Interior Minister

At least one gunman still on the run -- it is unclear how many attackers were present

No claim of responsibility has yet been made

US, Turkish officials say incident is a terrorist attack

Soylu also said that "the efforts to locate the terrorist are ongoing. Security forces have begun the necessary operations. God willing soon (the attacker) will be apprehended."

Around 1:15 a.m. Sunday, the gunman shot a police officer who was guarding the front gate at the Reina nightclub, killing him, Istanbul Governor Vasip Sahin said.

"He entered the club and attacked innocent people who were there to celebrate the new year. It was a cruel, cold-blooded act," the governor said.

There have been no claims of responsibility. The fate of the attacker -- or attackers -- was also unclear.

Photos: Attack at Istanbul nightclub This still photo, taken from surveillance footage and released on Monday, January 2, is believed to show the gunman responsible for carrying out a New Year's Day attack on the Reina nightclub in Istanbul. The popular nightclub was attacked shortly after midnight on Sunday, January 1. At least 39 people were killed and 69 were wounded, Turkey's Interior Minister said. Authorities are still searching for the attacker. Hide Caption 1 of 19 Photos: Attack at Istanbul nightclub A Turkish special forces officer stands near the Reina nightclub on January 2. ISIS claimed responsibility for the attack in a statement posted to Twitter. Hide Caption 2 of 19 Photos: Attack at Istanbul nightclub A friend of someone killed in the attack reacts near victims' pictures outside the nightclub on January 2. Hide Caption 3 of 19 Photos: Attack at Istanbul nightclub A police officer inspects cars near the scene on January 2. Hide Caption 4 of 19 Photos: Attack at Istanbul nightclub People carry the coffin of Yunus Gormek, a victim of the attack, during a funeral ceremony in Istanbul on January 2. Hide Caption 5 of 19 Photos: Attack at Istanbul nightclub People mourn outside the Forensic Medical Center in Istanbul on January 1. Hide Caption 6 of 19 Photos: Attack at Istanbul nightclub Relatives of Ayhan Arik, one of the victims of the attack, cry during a funeral ceremony in Istanbul on January 1. Hide Caption 7 of 19 Photos: Attack at Istanbul nightclub An ambulance rushes from the scene of the attack on January 1. Hide Caption 8 of 19 Photos: Attack at Istanbul nightclub A woman is consoled at the site of the attack. Hide Caption 9 of 19 Photos: Attack at Istanbul nightclub Medics wheel a stretcher at the scene. Hide Caption 10 of 19 Photos: Attack at Istanbul nightclub Police officers stand guard. Hide Caption 11 of 19 Photos: Attack at Istanbul nightclub People leave the scene of the attack. Hide Caption 12 of 19 Photos: Attack at Istanbul nightclub A medic reacts near the scene of the attack. Hide Caption 13 of 19 Photos: Attack at Istanbul nightclub Hide Caption 14 of 19 Photos: Attack at Istanbul nightclub A wounded victim is rushed from the scene. Hide Caption 15 of 19 Photos: Attack at Istanbul nightclub Medics and security officials work at the scene of the attack. Hide Caption 16 of 19 Photos: Attack at Istanbul nightclub A wounded person is put into an ambulance. Hide Caption 17 of 19 Photos: Attack at Istanbul nightclub People walk in the rain near the scene of the attack. Hide Caption 18 of 19 Photos: Attack at Istanbul nightclub An ambulance transports those wounded in the attack. Hide Caption 19 of 19

'Crazy people shooting everything'

Witnesses in the club said they heard a loud noise, then a security officer told everyone to get out.

One victim said he didn't know how many attackers there were, but he saw one person and hid.

"I got shot in the (expletive) leg, man," he told journalists in English as he was taken into an ambulance. "These crazy people came in shooting everything."

A security camera captured the moment a gunman dressed in dark clothing dashed into the Reina nightclub as bullets ricocheted in the street.

The assailant, who has not yet been identified, opened fire inside the high-end nightclub in the busy Besiktas neighborhood, according to Turkish state-run news agency Anadolu.

CNN Map

Besiktas, on the European shore of the Bosporus, is known for its expensive, upper-middle class neighborhoods. The popular area had been under heavy police security for new year celebrations.

Ortakoy, where Reina is located, is a vibrant seaside neighborhood that caters to a wide range of people, from the uber-rich who party at clubs like Reina, to students who buy stuffed baked potatoes from vendors along the Bosporus.

Reina itself is one of the first clubs to open along the famous strait and remains a touchstone for Istanbul's exclusive nightlife. It boasts a classic Istanbul view.

Several analysts said the attack looked more like a jihadist-inspired attack.

"In terms of the soft-target aspects of this attack, it's a youthful place, a bar that's pretty well-known in particular to expats. It's sort of the lively area of Istanbul, and especially on New Year's Eve night -- all of those have hallmarks of ISIS-inspired, if not directed attacks to maximize casualties and get a lot of news around it," said Juliette Kayyem, CNN's national security analyst.

Turkey's recent tumult

Turkey has endured a recent wave of terrorist attacks, leaving many people wary.

"This attack is, of course, a horrible development, but not shocking to many Turks who chose to stay inside this New Year's Eve," said Aykan Erdemir, former member of the Turkish Parliament.

"Turkey is known to host these big parties to celebrate New Year's, but this year most citizens were wary of Islamist attacks so they chose to celebrate it at home with their friends."

He said the attack seemed similar to what happened at the Bataclan, a Paris concert hall that was attacked by gunmen in 2015.

"This is an attack on the Western lifestyle. This is an attack on Turkey's secular, urban way of living. And this will simply fuel the ongoing cultural clashes, the ongoing polarization in Turkey," Erdemir said.

The United States condemned the attack.

"That such an atrocity could be perpetrated upon innocent revelers, many of whom were celebrating New Year's Eve, underscores the savagery of the attackers," National Security Council spokesman Ned Price said in a statement.

The US State Department said the attacks like this one on its NATO ally "only reinforce our strong determination to work with the government of Turkey to counter the scourge of terrorism."

The US Embassy in Turkey warned citizens to avoid the area where the attack occurred.

A violent year

Turkey faces numerous battles across different fronts. Not only has the Syrian conflict and refugee crisis spilled over into Turkey, but Turkey is also battling ISIS and Kurdish militants.

Both have staged attacks in Turkey, which is still reeling from a bloody and failed military coup in July.

ISIS is suspected in a June attack at Istanbul's Ataturk Airport that left 44 people dead and an explosion at an August wedding, not far from the border with Syria, that killed at least 54 people.

Meanwhile, Turkish security forces clash on an almost daily basis with Kurdistan Workers Party (PKK) militants, mostly in predominantly Kurdish parts of southeastern Turkey.

pair of bombings in Istanbul killed 44 people and wounded 155 others December 10 in an attack by a breakaway group of the PKK. The two explosions occurred after a heavily attended soccer game at Besiktas Vodafone Arena.