Officials believe gunman might have come from Central Asia

The Islamic State group on Monday claimed responsibility for an attack on a nightclub in the Turkish city of Istanbul that killed 39 people on New Year's Eve.

In a statement circulated on social media, the group said one of the "soldiers of the caliphate" had carried out the attack on the Reina nightclub.

Authorities also believe that the gunman, who killed 39 people, most of them foreigners, comes from a Central Asian nation, the Karar and Hurriyet newspapers reported, citing unnamed security sources.

Police had also established similarities with the high-casualty suicide bomb and gun attack at Istanbul's Ataturk Airport in June and was investigating whether the same IS cell could have carried out both attacks, the papers reported.

The gunman, who is still at large, killed a policeman and another man outside the club on Sunday before entering and firing at an estimated 600 people partying inside with an automatic rifle.

UN Secretary-General Antonio Guterres on Sunday condemned the "despicable terrorist attack". According to a statement, Guterres extended his deepest condolences to the families of the victims.

Nearly two-thirds of the dead in the upscale club, which is frequented by local celebrities, were foreigners, Turkey's Anadolu Agency said. Many of them hailed from the Middle East.

The mass shooting followed more than 30 violent acts over the past year in Turkey, which is a member of the NATO alliance and a partner in the US-led coalition fighting against the IS group in Syria and Iraq. The country endured multiple bombings in 2016, including three in Istanbul alone that authorities blamed on the group.