Fears are growing over the fate of a Pakistani activist who has been reported missing since the weekend.

Raza Khan from Lahore disappeared after attending a public discussion on a recent, controversial protest by a hardline religious group.

Earlier this year a number of social media activists were "disappeared," before being released.

Two later told the BBC a "state agency" had abducted and tortured them. The military denied any involvement.

On Saturday Mr Khan helped organise a small public event in Lahore which discussed the recent sit-in by a new Islamist political party.

That protest, accusing a government minister of committing blasphemy, had caused mass disruption in the capital Islamabad, turning violent when police attempted to intervene.

The army had then facilitated an agreement between the demonstrators and the government, resulting in the minister's resignation and all the protesters' other demands being met.

Some commentators have accused the military of secretly supporting the protests and attacked the terms of the agreement as a capitulation to extremists. The Pakistani army, though, denies interfering in politics.

Umair Vahidi, a friend of Mr Khan's who was also at the public meeting, said it had been a "frank and open discussion".

He added: "People shared their conflicting points of view... There was no hostility."

Blasphemy laws "and how they can be used to target minorities" had also been discussed, Mr Vahidi said.

Calls unanswered

Mr Vahidi told the BBC the discussion had finished around 20:00 when all of the participants when home. That was the last he or any of his friends heard from Mr Khan.

"I started calling Raza at about 13:30 on Sunday and his phone was off. We started calling his friends."

After being unable to contact him throughout the day, Mr Vahidi and a group of other friends visited his house at about 23:30 on Sunday.

"His light was switched on," he said. "That was unusual."

The door was locked, he added, and "nothing was missing from his room. There were no signs of struggle… The neighbours, the landlord, nobody knew anything."

However, on a later search Mr Vahidi said they noticed while Mr Khan's computer screen was still in his room, the computer base unit was missing.

Civil rights campaigners have raised concerns about a crackdown on dissenting voices in Pakistan since six bloggers went missing in January this year.

Mr Vahidi told the BBC he was not aware of Mr Khan having received any threats, but said he had told him some of the people attending his events "would sign the register with different names each time".

Mr Khan's brother has reported the case to the police, saying it appears he was kidnapped.