Addressing a hurriedly called press conference at the JKLF office here, Geelani and Mirwaiz Umer -- who spoke to the media over telephone -- and Malik alleged that the Indian government was engaged in an operation to "wipe out" the people of Kashmir.
Geelani said that attempts by New Delhi to break the "will and resolve of the freedom seeking people of Kashmir" would never succeed.
The separatists called for a Valley-wide protest shutdown on Thursday and Friday against Wednesday's civilian killings in Kulgam district.
After the press conference, Malik started a protest march towards the city centre Lal Chowk along with some supporters.
Police intervened to break the march. Malik was detained.
As news about Malik's arrest reached the uptown Maisuma area, youths poured out of their homes and clashed with security forces.
Clashes have also been reported against Wednesday's civilian killings in Pulwama, Anantnag, Sopore and Bandipora towns.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)