ISTANBUL • A 34-year-old Uzbek man suspected of killing 39 people at an Istanbul nightclub in the early hours of the new year confessed to the massacre yesterday, hours after his capture in a police raid.

The authorities detained Abdulgadir Masharipov - who spent 17 days on the run after the attack claimed by the Islamic State in Iraq and Syria (ISIS) group - along with three women and an Iraqi man during a massive police operation in Istanbul.

"The terrorist confessed his crime," Istanbul Governor Vasip Sahin told reporters, saying the suspect's fingerprints matched those of the attacker and confirming that he is an Uzbek national.

"He was trained in Afghanistan and can speak four languages. He is a well-trained terrorist," added the Governor, saying that Masharipov is believed to have first entered Turkey in January last year.

The police also confiscated US$197,000 (S$280,000), two firearms and clips during the raid on an apartment, he added.

The arrest has lessened the anxiety of Istanbul residents, already on edge after a string of attacks, who had feared for more than a fortnight that a trained killer was on the loose in the city.

Local media published a picture of the detained man with blood on his face and T-shirt, his neck gripped by a policeman.

Turkish President Recep Tayyip Erdogan hailed the arrest and congratulated the security forces. "From now on in this country, nobody will get away with what they have done," he said in a speech in Ankara. "Everyone will be brought to account within the rule of law."

The operation to capture the suspected terrorist involved some 2,000 police officers, the Istanbul Governor said.

The suspect had apparently slipped into the night following the attack on the glamorous Reina nightclub on the Bosphorus, while police tightened borders to prevent him from escaping. But he was hiding in the working-class, densely populated western districts of Istanbul. Days of police tracking eventually traced him to an apartment in the residential Esenyurt district.

An Iraqi man was detained with him, as well as three women, one an Egyptian citizen and two others from African states, Mr Sahin said. All the suspects are currently still being interrogated at the police headquarters, he added.

The ISIS extremist group took responsibility for the bloodbath, the first time it had ever openly claimed a major attack in Turkey.

It had previously been blamed for several strikes in Turkey, including the triple suicide bombing at Istanbul airport last June.

There had been confusion over the attacker's identity in the wake of the New Year massacre, with reports initially suggesting that a Kyrgyz national and then a Uighur from China was responsible.

But the authorities later identified him as a 34-year-old Uzbek who was part of a Central Asian ISIS cell using the code name Ebu Muhammed Horasani.

Images released by police during the manhunt were taken from a chilling silent video he purportedly took at Istanbul's Taksim Square with a selfie stick, before carrying out the carnage.

According to NTV television, the attacker was captured at 12.15am. The police had found his location three days earlier, but decided to track him to identify his contacts.

A total of 50 people have now been detained in the investigation as a result of 152 raids since the attack, Mr Sahin said.

Of the 39 killed in the Reina attack, 27 were foreigners, including citizens from Lebanon, Saudi Arabia, Israel, Iraq and Morocco.

AGENCE FRANCE-PRESSE