Hardline religious protesters threw stones at supporters of five missing Pakistani activists on Thursday and demanded that police charge the missing men under a blasphemy law that carries a mandatory death sentence.
The liberal activists, who have posted blogs criticizing the political influence of the military and speaking up for the rights of religious minorities, have all gone missing separately since Jan. 4, and it is unclear what happened to them.
Shortly after their disappearances, blasphemy allegations against them appeared on social media and in a complaint to police.
Critics of Pakistan's blasphemy laws say they have long been used by individuals and religious groups to settle disputes.
About 100 members of a little-known religious group, Tehreek Labaik Ya Rasool Allah, arrived at the local press club in the port city of Karachi and started hurling stones at people gathered there to support the missing activists.
They chanted slogans asking police to file blasphemy cases against the missing activists and carried banners that read:
"Beheading is the punishment of blasphemers."
The activists' supporters were forced to withdraw into a nearby building.
"We persuaded the religious activists to withdraw," police officer Aurengzeb Khan said. "Their leader then held prayers for the prosperity of Islam and called on the members to leave."
Friends, family and supporters of all five men deny they have blasphemed, and have denounced the campaign to press that charge, which could endanger their lives were they to reappear.
The Interior Ministry said on Thursday that police had not registered a blasphemy case, although police in Islamabad confirmed on Wednesday that a formal complaint had been made by a lawyer.
"There is absolutely no truth to reports that cases have been filed against the bloggers," the ministry said. Interior Minister Nisar Ali Khan was quoted last week as saying the government was not responsible for the disappearances.