Turkish authorities have identified the gunman who shot dead dozens of revellers at a nightclub in Istanbul on New Year's Eve, Turkey's top diplomat said, as police stepped up raids against suspected militant hideouts as part of the hunt for the attacker who is still at large.

The rampage on Sunday, which killed 39 people from more than a dozen countries, was claimed by Isis (Islamic State) and marked one of the worst mass killings in Turkey in recent memory.

It also put Turkey further on edge following a steady string of violence, including the assassination of the Russian Ambassador last month and earlier bombings targeting police and tourist sites.

Speaking to the state-run Anadolu news agency, Foreign Minister Mevlut Cavusoglu gave no further details on the suspect's identity, but said the investigation is ongoing.

Advertisement

"The home he stayed in has been found and investigated - also, his connections and who has helped him," he said, adding that the Interior Ministry is working diligently to find the attacker.

He also said the attack appeared to have been "prepared professionally".

In a nationwide address, Turkish President Re├žep Tayyip Erdogan said the carnage sought to divide Turkey, but the nation will not fall "for this game".

Erdogan, however, tried to reassure Western-looking Turks who are increasingly alarmed about Islamists forces gaining footholds in a country with strong secular traditions going back nearly a century.

"In Turkey," Erdogan said, "no one's way of life is under any threat. Those who claim this have to prove it. It is my duty to protect everyone's rights."

Official information about the attacker is scarce, and the Turkish press has given conflicting accounts of the man's identity and path he followed to the club, where hundreds of people were celebrating the New Year.

The attack occurred just after 1am local time, when the gunman shot his way into the post night club, sparking panic. Nearly 70 people were also wounded in the mayhem.

In recent days, police have released a blurry photograph of the alleged attacker, in what appears to have been taken from surveillance camera footage, and the press carried a selfie video purported to be of the suspect. It was unclear how the cellphone video was obtained.

Turkish police raided homes today in the city of Izmir on the Aegean coast, Anadolu reported, and detained at least five people linked to the attack. The arrests follow similar raids in the central province of Konya, where the attacker is believed to have rented an apartment, according to Turkish media reports. There were no further details on those arrested.

Turkey's military has backed an offensive by Syrian rebels to oust Isis from areas near its border, and Turkish warplanes and artillery have pounded the militants' positions inside Syria for months.