Updated

Pakistani police have blocked a rally by clerics in Islamabad seeking to press their calls for the death of social media activists accused of insulting Islam.

Security forces sealed off and surrounded the Red Mosque and the home of the leader, Maulana Abdul Aziz, preventing his followers from staging the gathering on Friday.

Meanwhile, the Center for Inquiry, a U.S.-based advocacy group, has appealed to Facebook not to consider demands by Pakistan to help identify Pakistanis suspected of blasphemy so that authorities can prosecute them or pursue their extradition.

Pakistan has harsh blasphemy laws under which insulting Islam is an offence that carries the death penalty.

Pakistan's media have been increasingly attacked by religious hard-liners. The government has asked Facebook and Twitter to censor religiously offensive material emanating from Pakistan.