Istanbul police conducted simultaneous operations at multiple districts to detain 82 foreigners, Anadolu Agency reported. The suspects had allegedly been active in conflict zones with IS and planned on going to Syria.
Separately, Anadolu said 11 Syrian nationals were detained in the southern province of Adana for alleged links to IS. Seven others, whose nationalities weren't revealed, were detained in western Izmir province. The nationalities of the 82 foreigners detained in Istanbul also weren't disclosed.
The operations are part of Turkey's ramped up effort to clamp down on IS. Police detained more than 170 IS suspects in a sweep in the capital, Ankara, on Thursday.
The Istanbul detentions were part of operations to protect Friday commemorations of the 79th anniversary of founder Mustafa Kemal Ataturk's death as well as securing an Istanbul marathon scheduled for Sunday, according to the private Dogan news agency.
Turkey has suffered a series of bloody attacks blamed on IS militants, including a New Year's attack at an Istanbul nightclub by a gunman that killed 39 people.
Last month, police said they broke up sleeper cells and detained dozens of IS suspects allegedly planning an attack during a national holiday. A bomb-laden vehicle and motorcycle set up to be detonated with remote controls were discovered outside a mall in Istanbul, along with suicide vests, according to Anadolu.
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