1106 GMT January 19, 2020
Police have launched almost daily operations against Daesh cells across the country following concerns hundreds of alleged members of the terror group have crossed into Turkey from Syria, AFP wrote.
The suspects were detained during raids on 12 addresses in eight districts of Istanbul, the privately-owned news agency Dogan said.
They are suspected of providing financial support to terrorists in "conflict zones", with the authorities opening deportation proceedings against them, it said.
Earlier this month, Dogan said nearly 800 alleged Daesh members had illegally crossed into Turkey from Syria, though it did not say over what period.
Police detained 634 Daesh suspects last month, according to Interior Ministry figures.
Over the past two years, Turkey has suffered a series of attacks blamed on Daesh, one of which targeted a popular Istanbul nightclub during New Year celebrations, leaving 39 people dead.
Daesh gunman Abdulgadir Masharipov, who was born in Uzbekistan and confessed to the attack, will go on trial this month.
There are concerns that those foreigners who have fought in Syria or Iraq will pose security risks on their return home as Daesh loses significant territory in the two countries.
At least 5,600 people, residents of 33 countries, have returned home, the Soufan Center, a nonprofit security analysis group, said in October.
Prime Minister Binali Yildirim on Friday claimed Turkey had stopped a total of 50,000 "foreign fighters" although he did not say over what period. This figure is believed to include those who have been blocked at Turkish airports.
He also said Turkey had caught 5,000 Daesh suspects.