Authorities say they are looking for this man in connection with the deadly attack.
Eight people have been detained in connection with the attack, Kurtulmus said, but the suspect was not among them.
“There is strong coordination and we will find him, no delay,” Turkish Prime Minister Binali Yildirim said.
Footage of the attacker shooting a security guard and police officer at the entrance of the nightclub has emerged, and Turkish authorities said they believe he carried out the attack alone.
Earlier Monday, the militant Kurdistan Worker’s Party, or PKK, distanced itself from the attack.
“No Kurdish forces have anything to do with this attack,” the PKK said in a statement. “The Kurdish freedom fight is also the fight for democratization of Turkey. That’s why we won’t target innocent and civilian people.”
Those killed in the attack were from 14 countries, including India, Morocco, Jordan, Canada, Russia, Tunisia, Saudi Arabia and Kuwait.
Security guard Fatih Cakmak was one of the first victims killed. He had considered himself lucky after surviving a December attack outside Istanbul’s Vodafone Arena, where he was also working security.
“He went to work, and now he’s gone,” said his father Hassan Cakmak, who said he can’t believe he survived his 32-year-old son.
Lubna Ghaznawi, a young female entrepreneur from Saudi Arabia, was also killed. The 34-year-old worked full-time as a communications manager for one of Saudi Arabia’s largest banks and also co-owned a start-up with her sister called Exclusave Card, the first student discount card in Saudi Arabia.
“She was an optimist and loved going to new places,” her friend Seham al-Shahrani told CNN. Laughter and happiness filled whatever place she went to.”
The industrious 34-year-old worked full-time as a communications manager for one of Saudi Arabia’s largest banks and also co-owned a start-up with her sister called Exclusave Card, the first student discount card in Saudi Arabia.
Dozens of people were hospitalized. As of Monday, 46 were still being treated, including one American, according to the Istanbul governor’s office. A handful of the injured were in critical condition.
‘We were having fun’
Witnesses described how the festive evening turned into a bloodbath.
“We were having fun. At first we thought it was a fight, then there was a lot of gunfire,” witness Yunus Turk told CNN.
“After the gunfire everyone started to run toward the terrace. We ran as well. There was someone next to me who was shot and fell on the floor. We ran away and hid under the sofas.”
Another witness said he didn’t know how many attackers there were, but he saw one person and hid.
“I got shot in the f****** leg, man,” he told journalists as he was taken into an ambulance. “These crazy people came in shooting everything.”
Why are attacks so frequent in Turkey?02:13
On Sunday, the club issued a statement on its Facebook page.
“This terrible incident is a terror attack against our citizens’ peace, brotherhood, serenity, economy, tourism and against our nation,” the statement read.
“Our hearts bleed and the bullets are in our heart.”
A violent year
Both ISIS and Kurdish militants have staged attacks in Turkey, which is still reeling from a bloody and failed military coup in July.