ISLAMABAD: Prime Minister Nawaz Sharif strongly condemned on Wednesday the brutal murder of a Christian couple in Kot Radha Kishan and termed it "an unacceptable crime".

"A responsible state cannot tolerate mob rule and public lynching with impunity," Prime Minister Nawaz said.

"I have directed Punjab Chief Minister to show no mercy and law should take its course to punish those who are responsible for this act," the premier remarked.

The Prime Minister said Pakistani state has to act pro-actively to protect its minorities from violence and injustice and to promote inter faith harmony among various religions.

According to police, an enraged mob had beaten a Christian couple to death and burnt their bodies in the brick kiln where they worked for allegedly desecrating a copy of the Holy Quran.

The incident had taken place at the town of Kot Radha Kishan, some 60 kilometres southwest of Lahore, and was the latest example of mob violence against minorities accused of blasphemy.

Read: Christian couple beaten to death for 'desecrating Quran'

“A mob attacked a Christian couple after accusing them of desecration of the Holy Quran and later burnt their bodies at a brick kiln where they worked,” local police station official Bin-Yameen had said.

The victims were only identified by their first names, Shama and Shehzad, and were a married couple.

Pakistan's brick kiln workers are often subject to harsh practices, with a study by the Bonded Labour Liberation Front Pakistan estimating that 4.5 million are indentured labourers.

Punjab Chief Minister Shahbaz Sharif has constituted a three-member committee to fast track the investigation of the killings and ordered police to beef up security at Christian neighbourhoods in the province, an official from his media office said.

Read: Salman Taseer's killer incited shooting of elderly blasphemy inmate

Blasphemy is a hugely sensitive issue in the country, with even unproven allegations often prompting mob violence. Anyone convicted, or even just accused, of insulting Islam, risks a violent and bloody death at the hands of vigilantes.

A Christian woman, Aasia Bibi, has been on death row since November 2010 after she was found guilty of making derogatory remarks about Prophet Muhammad (PBUH) during an argument with a Muslim woman.

An elderly British man with severe mental illness, sentenced to death for blasphemy in January, was shot by a prison guard few days ago.