Turkish police have carried out a dawn raid in a town on the edge of Istanbul and detained suspects thought to be linked to the nightclub attack which killed 39 people on New Year's Day, the state-run Anadolu news agency reports.
Counter-terrorism police, gendarmes and special forces swooped on a housing complex in Selimpasa, a coastal town just to the west of Istanbul, after receiving intelligence that individuals who may have helped the gunman were there.
The gunman, who is still at large, shot his way into exclusive Istanbul nightclub Reina early on Sunday and opened fire with an automatic rifle, throwing stun grenades to allow himself to reload and shooting the wounded on the ground.
Separately Deputy Prime Minister Veysi Kaynak said the gunman is probably Uighur and Turkey has established his possible locations and links.
In an interview with broadcaster A Haber, Kaynak said he could not rule out the possibility of the attacker fleeing abroad but that operations within Turkey were more likely to achieve a result.
He said the gunman acted alone but may have been helped by others.
Islamic State claimed responsibility for the attack, saying it was revenge for Turkish military involvement in Syria.
It was not immediately clear how many people were detained on Thursday, but at least 36 people have been held since the attack, according to earlier media reports.
Police in the Aegean coastal city of Izmir on Wednesday detained what they said were 20 suspected Islamic State militants thought to be of Central Asian and North African origin. Fake passports, mobile phones, and equipment including night vision goggles and a GPS device were seized.
Turkey's foreign minister said on Wednesday the identity of the gunman had been established but did not give further details. The authorities have not named the suspect.
The nightclub attack in Istanbul's upscale Ortakoy district on the shore of the Bosphorus followed a failed coup in July and a series of attacks by radical Islamist and Kurdish militants which have shaken NATO member Turkey over the last year.
President Tayyip Erdogan said the attack on the club, popular with local celebrities and wealthy foreigners, was being exploited to try to divide the largely Sunni Muslim nation.
Among those killed in the attack were Turks and visitors from several Arab nations, India and Canada.
