Six leaders from the hardline faction of the Hurriyat Conference led by Syed Ali Shah Geelani were detained in Srinagar on Thursday just before they were to address a press conference.
The police action came four days after a case was registered against Geelani and four others under section 13 of the Unlawful Activities Act after a rally in Srinagar on April 22 during which participants shouted pro-terrorism slogans.
A police team waiting outside a hotel, the venue of the press conference, detained the six separatists, including the faction's acting chairman GN Sumji, as soon as the event began.
Sumji, Masrat Alam, Mohammed Shafi Lone, Firdous Ahmad Shah, Mohammed Yasin and Mehrajuddin, who resisted their detention and shouted pro-freedom slogans, were whisked away from the hotel and bundled into a police vehicle.
They were taken to Kothibagh police station.
Alam was one of the persons named in the case registered following Sunday's rally.
Another Hurriyat leader, advocate Mohammad Shafi, who was not detained by police, claimed today's action indicated the government's "frustration".