Separatist leader Yasin Malik was taken into preventive custody by police on Tuesday from his office at Abi Guzar in the city, officials said.
They did not cite the reason for Malik's detention but the JKLF claimed the action was taken due to the urban local bodies polls which are beginning on October 8.
Separatists including Malik have called for a boycott of these elections.
In a statement issued by Jammu Kashmir Liberation Front (JKLF), Malik said in a democracy people are given space to expresses their views and participation in or boycotting elections is also a democratic right.