Turkish police have begun questioning a suspected Islamic State militant accused of killing 39 people during a New Year's attack on an Istanbul nightclub.
The gunman, which the media reports named as Uzbekistan national Abdulgadir Masharipov, was caught late on Monday in a police operation at a luxury residential complex in the Turkish capital.
The state-run Anadolu Agency said a man from Kyrgyzstan and three women - from Somalia, Senegal and Egypt - were also detained in the raid, while the gunman's four-year-old son was taken under protective custody.
Islamic State had claimed responsibility for the nightclub massacre, saying the attack in the first hours of January 1 was in reprisal for Turkish military operations in northern Syria.
The man named as the suspect had been on the run since the attack.
Private NTV television said Masharipov and the four other suspects were being questioned at Istanbul's police headquarters on Tuesday.
Istanbul's governor and police chief were scheduled to make a statement later on Tuesday.
Anadolu said police have also carried out raids on members of a suspected Uzbek IS cell in five Istanbul neighbourhoods, and detained several people.
Authorities had set up a 1000-person force to capture the gunman, Anadolu said.
Photographs from raids, published in the Turkish media, showed a bruised, black-haired man in a grey, bloodied shirt being held by his neck.
NTV television said the gunman had resisted arrest.
Hundreds of people were gathered at the swanky Reina nightclub to celebrate the end of a tumultuous 2016 only to become the first victims of 2017.
The gunman shot a police officer and a civilian outside the club before storming the premises.
Most of the dead in the attack on the upscale club were foreign nationals, mainly from the Middle East.