UPDATE: 01/01/17 6:09 a.m. EST
Authorities have launched a manhunt for an unnamed suspect who opened fire at Reina nightclub during New Year's celebrations in Istanbul.
The death toll from the attack has risen to 39, 15 of which were foreign nationals, according to Turkey's interior minister. Another 70 were wounded.
Officials said the assailant was believed to have been dressed in a Santa Claus costume at the time of the attack.
Turkish President Recep Tayyip Erdogan, along with other foreign leaders, condemned the attack.
"I vehemently condemn the terror attack in Istanbul's Ortakoy neighborhood in the first hours of 2017," Erdogan said in a written statement Sunday.
He also pledged to "do whatever is necessary in the region to ensure its citizens' safety and peace."
The White House condemned the attack and offered help to Turkey.
WNBA players next door to deadly shooting
Several WNBA players were right next door to the nightclub when it came under attack.
Los Angeles Sparks coach Brian Agler confirmed that players Essence Carson, Chelsea Gray and Jantel Lavender had texted him saying they were OK.
The three Sparks players are among about two dozen WNBA players participating in a league in Turkey during the offseason.
Turkey's state-run news agency says an armed assailant has opened fire at a nightclub in Istanbul during New Year's celebrations, wounding several people.
The Anadolu Agency said the attack occurred in Istanbul's Ortakoy district.
Footage from the scene showed at least six ambulances with flashing lights and civilians being escorted out. Media reports said police have cordoned off the area and an operation is ongoing.
Istanbul's governor says at least 35 people were killed in the attack at a nightclub in Istanbul during New Year's celebrations.
Vasip Sahin said some 40 other people were wounded in the assault in the early hours of Sunday.
Sahin said the incident was a "terror attack" without saying who may have carried it out.
Turkish police had already announced that they've arrested two people with alleged ties to ISIS on suspicion of planning a New Year's Eve attack. The pair were in possession of explosives and shrapnel.
Investigators believe the two were planning to target two locations near Ankara's Kizilay district.
(The Associated Press contributed to this report)