The Istanbul nightclub attack on New Year's Eve was carried out professionally and an intelligence organisation was involved, Turkey's deputy prime minister has said.
"It appears the Reina [nightclub] attack is not just a terrorist organisation's act, but there was also an intelligence organisation involved. It was an extremely planned and organised act," Norman Kurtulmus said during an interview with broadcaster A Haber on Monday.
The deadly assault in which a gunman shot a police officer and security guard before entering the upmarket nightclub to spray New Year's Eve partygoers with bullets was claimed by Isis.
Thirty-nine people were killed and 70 injured in the attack which served as revenge for Turkish involvement in the Syrian civil war, the group claimed.
Dozens of people across Turkey have been arrested and questioned in connection to the assault in the last two weeks. Police say they know the identity of the alleged attacker - who remains at large - but have not released his name.
The authorities previously said that they believe the gunman acted alone, but may have belonged to a cell or had help in planning.
The suspect is thought to be of ethnic Uighur origin, from a central Asian country. The Uighur are a largely Muslim Turkic-speaking minority from far Western China, with a significant diaspora community in Turkey.
Overnight on Sunday two Chinese nationals were arrested in relation to the attack, police said.
