The arrests came after police raids in several districts of Istanbul and the seizure of bomb-making equipment and documents, the agency said.
The detainees are believed to have been targeting a public institution, which was not identified, and to have been behind seven previous bomb attacks against offices and vehicles.
The news came as Prime Minister Tayyip Erdogan confirmed his government’s plans for a state TV channel to broadcast in the Kurdish language, part of reforms he hopes will help sap support for the PKK rebels in Turkey’s mainly Kurdish southeast.
Ankara blames the PKK for the deaths of nearly 40,000 people, mostly Kurds, since the group launched its armed campaign for an ethnic homeland in southeast Turkey in 1984.
Much of the violence has been concentrated in Turkey’s impoverished southeast, though PKK militants have also staged attacks in Istanbul and other western Turkish cities and towns.
Turkish troops recently staged a major eight-day ground offensive into mountainous northern Iraq to crush PKK rebels using the region as a base from which to attack Turkey.