A baby girl, her seven-year-old sister and their grandmother suffocated to death after a Pakistani mob set fire to the homes of Ahmadi Muslims in protest at a Facebook post by a young man. An expectant mother also miscarried her baby after the attack.

It happened after an argument between some men in Gujranwala town, 140 miles southeast of Islamabad, on 27 July.

The young man, who was not injured, is alleged to have posted a blasphemous photo with nudity showing the Kaaba shrine at the Grand Mosque in Mecca, Saudi Arabia, according to local police official Zeeshan Siddiqi.

A crowd of 150 people then went to a police station and demanded a blasphemy case should be registered against the man. At the same time another mob appeared and began burning the houses inhabited by the Ahmadi community.

Salim ud Din, from the Ahmadi community, said it was the worst attack suffered by the group since 86 Ahmadis were killed during a mob spree four years ago against places of worship. He said police did not try to stop the mob – an accusation denied by police.

He said: “First they looted their homes and shops and then they burnt the homes.”

The Ahmadis are a religious group which claim an identity as Muslims but they believe in another prophet after Mohammed. They are considered non-Muslims by a law passed in Pakistan in 1984 and are one of the ‘most relentlessly persecuted communities’ in the country, according to the BBC. They are not allowed to use Muslim greetings, say Muslim prayers or refer to their worship place as a mosque.

Some 100 people have been accused of blasphemy under Pakistani legislation this year, to date, according to The Telegraph.