Gunman identified in Istanbul nightclub attack, Turkish authorities say

The gunman who killed 39 people in the New Year's nightclub terror attack in Istanbul has been identified by Turkish authorities.

Turkish Foreign Minister Mevlut Çavusoglu announced the development Wednesday but did not name the suspect or provide the suspect's nationality.

Authorities have also detained five alleged ISIS members in connection with the attack, state-run agency Anadolu reported Wednesday.

At least 21 people are being held in connection with the attack, though the gunman who carried out the attack at the Reina nightclub in Istanbul still at large.

According to Anadolu, the five were picked up in the Aegean province of Izmir.

ISIS claimed responsibility for the attack in a statement posted to Twitter, but the claim cannot be independently verified by CNN. It boasted about the first major terrorist attack of 2017.