A strike is taking place across Pakistan to protest against possible changes to the blasphemy laws. No public transport was reported in Karachi, where demonstrators blocked traffic as part of the industrial action called by religious parties. The government has distanced itself from a bill to change the law, which carries a mandatory death sentence for anyone who insults Islam. Rights groups say the law is often used to persecute religious minorities. Traffic was thin in Karachi, and there were reports of businesses shut in parts of Sindh and Punjab provinces, says the BBC's Ilyas Khan in Islamabad. There were also reports of a transport strike in Quetta, the capital of the southern province of Balochistan. Religious parties have planned a series of protests against any attempt to amend the blasphemy law. Although no-one convicted under the law has been executed, more than 30 accused have been killed by lynch mobs. The legislation returned to the spotlight in November after a Pakistani Christian woman, Asia Bibi, was sentenced to death. Friday's strike was organised to protest against a private bill submitted to parliament. It seeks to amend the law by abolishing the death sentence and by strengthening clauses which prevent any chance of a miscarriage of justice. Source: BBC The bill has been drafted by a member of the ruling Pakistan People's Party and by a former Information Minister, Sherry Rehman. This led religious groups to conclude the government was behind it. On Wednesday, Pakistan's religious affairs minister told parliament the bill did not reflect government policy. "I state with full responsibility that the government has no intention to repeal the blasphemy law," Syed Khurshid Shah said. "If someone has brought in a private bill, it has nothing to do with the government." Our correspondent says Mr Shah's remarks are meant to placate shrill religious protest at a time when the government is grappling with two estranged allies - the Muttahida Qaumi Movement and the Jamiat-i-Ulema Islami of Maulana Fazlur Rahman. Many believe the two are acting at the behest of the security establishment to undermine the country's political system. The Pope has led international calls to show mercy on Asia Bibi, who denies insulting the Prophet Muhammad during an argument with other farmhands in a Punjab province village in June 2009.