Turkish police have detained 31 suspected Islamic State members in Istanbul who were preparing to launch an attack, state-run Anadolu news agency reported on Saturday.
Police raided six addresses in three districts of the city, Anadolu said, without giving details on when the operations were carried out.
All of those detained were foreign nationals, reports Reuters citing the agency.
Officers seized digital material and documents during the operation.
Turkey has been a partner in the US-led coalition against Islamic State fighters.
Turkish police stepped up operations against Islamic State suspects at the end of last year before the first anniversary of a New Year gun attack on a nightclub in Istanbul in which 39 people were killed.
Islamic State claimed responsibility for that shooting, one of a series of attacks believed to have been carried out by the jihadists in Turkey in recent years.