The insurgent leaders invited to speak were Hafiz Muhammad Saeed, a founder of the banned Lashkar-e-Taiba group, whom India accuses of masterminding the 2008 commando-style assault in Mumbai that killed 166 people, and Syed Salahuddin, chairman of an umbrella group United Jihad Council.

Police raided the conference hall in a Srinagar hotel an hour before it was to begin and arrested Ahsan Untoo, chairman of Human Rights Forum Jammu-Kashmir, said Farooq Ahmed, a top police officer.

Srinagar is the main city in the Indian portion of Kashmir.

Ahmed said Untoo was arrested for supporting and promoting the ideology of insurgent leader Saeed. “It's unacceptable,” he said.

Police also detained four others including Javaid Ahmed Mir, a senior separatist leader.

Untoo said the police action violated his right of freedom of expression as he had organized the conference to discuss unity among separatist groups.

“They (Saeed and Salahuddin) were not the only people to speak, but guests included top human rights defenders and separatist leaders from our side of Kashmir as well,” Untoo told reporters as the police took him away.