Islamic State hailed the "heroic soldier of the caliphate" who carried out the attack
New footage has been released which appears to show the suspected gunman in the Istanbul attack filming himself walking around the popular tourist destination of Taksim Square.
The video comes as police continue to launch raids in the hunt for the attacker who killed 39 people in a nightclub on New Year's Eve.
Deputy prime minister Numan Kurtulmus said authorities are close to identifying the gunman after finding his fingerprints and getting a basic description of him.
It is reported that 12 arrests have been made in connection with the attack, which has been claimed by Islamic State.
The militant group hailed the "heroic soldier of the caliphate" who carried out the attack, which it said was in revenge for Turkish military involvement in Syria.
On Monday, more than 100 Islamic State targets were hit by Turkish and Russian jets in retaliation.
Police are said to be investigating whether the killer belonged to the same terror cell that carried out a deadly suicide bombing and gun attack at Istanbul's Ataturk airport last June.
There are also reports Turkey received an intelligence tip-off from the US about the threat of a New Year attack, although it did not give details of where it could take place.
Most of those who died in the nightclub attack were foreigners - with citizens from Saudi Arabia, Lebanon, Libya, India and Canada among those killed at the venue on the banks of the Bosphorus.
None of the 25 foreign citizens who died are thought to be British.
The Foreign and Commonwealth Office (FCO) said UK tourists should follow the advice of local authorities.