At least 24 people were arrested in the raids in the Okmeydani district of Istanbul as dozens of police deployed in armoured vehicles in the area, Turkish media said.
Police also seized firearms, documents, computers, a large number of bullets and communications devices.
The raids came two days after a prosecutor was killed in Istanbul in a hostage-taking blamed on the far-left Revolutionary People's Liberation Party-Front (DHKP-C).
Yesterday, a militant tried to storm the police headquarters in Istanbul. Police opened fire in response, killing the female assailant who was armed with grenades and guns.
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Turkish media named the dead woman as Elif Sultan Kalsen, 28, saying she was a known member of the DHKP-C.
Initial reports said she had a male accomplice who escaped and was then arrested. However the CNN-Turk channel said Monday that the person was a passer-by who had been wounded in the crossfire.
It also claimed a suicide attack in Istanbul later that month but, amid a bizarre sequence of events then withdrew the claim, saying it had made a mistake.
It had said at the time that the suicide bomber was Elif Sultan Kalsen but her parents then said the body was not hers. She has been missing ever since.
The authorities then indicated the bomber was a Russian woman from the Caucasus who had married an Islamist jihadist.
The Istanbul prosecutor who was killed after being taken hostage by DHKP-C militants, Mehmet Selim Kiraz,was himself investigating the Elvan case.