Islamic State has claimed responsibility on Monday for a New Year's Day mass shooting in a packed Istanbul nightclub that killed 39 people, an attack carried out by a lone gunman who remains at large.
The jihadist group made the claim in a statement on one of its Telegram channels, a method it has used to claim attacks in the past.
"In continuation of the blessed operations that Islamic State is conducting against the protector of the cross, Turkey, a heroic soldier of the caliphate struck one of the most famous nightclubs where the Christians celebrate their apostate holiday," the statement said.
NATO member Turkey is part of the US-led coalition against Islamic State and launched an incursion into Syria in August to drive the radical Sunni militants from its borders.
The authorities believe the assailant may be from a Central Asian nation and suspect he had links to Islamic State, Turkey's Hurriyet newspaper said.