ISLAMABAD, Pakistan — In the latest blasphemy case to highlight growing intolerance in Pakistan, the police in Punjab Province said Tuesday that they had filed blasphemy charges against a group of 68 lawyers at the instigation of a Sunni extremist leader.

The mass charging was an unusually wide application of Pakistan’s colonial-era blasphemy law, which carries a potential death sentence. But it was consistent with what human rights groups call an increasingly frequent abuse of the law to settle scores, silence opponents or persecute minorities, and comes at a time when freedom of expression in Pakistan is under concerted assault from extremists.

“Blasphemy has become a political battle,” said I. A. Rehman, a veteran human rights activist. “It’s no longer just a criminal or religious problem — it’s become a political issue that is used to silence voices and create a climate of fear.”

Mr. Rehman’s family suffered directly from the blasphemy laws last week. His nephew, a prominent defense lawyer and rights activist named Rashid Rehman, was shot dead in the southern city of Multan, weeks after he received death threats for defending a university lecturer accused of blasphemy.