A 41-year-old man has been stoned to death by a mob for allegedly desecrating the Koran inside a mosque in a village in eastern Pakistan, police have said.

Three police officers also were injured, and more than 80 men have been detained after the incident on Saturday evening in the Khanewal district of Punjab province.

The mosque’s custodian said he saw the man burning the Muslim holy book and told others before informing police, according to a spokesman.

Police rushed to the mosque and found the man surrounded by an angry crowd.

Officer Mohammad Iqbal and two other police personnel tried to take custody of the man, but the group began throwing stones at them, seriously injuring Mr Iqbal and slightly injuring the other two officers.

Munawar Gujjar, chief of Tulamba police station, said he rushed reinforcements to the mosque but they were not in time to stop the mob stoning the man to death before hanging his body from a tree.

The victim was named as Mushtaq Ahmed, 41, who was from a nearby village.

“The ill-fated man has been mentally unstable for the last 15 years and according to his family often went missing from home for days begging and eating whatever he could find,” he said.

Mr Ahmed’s body has been returned to his family.

Police have so far detained about 80 men living in the mosque’s surroundings, but around 300 suspects are said to have taken part in the stoning.

Pakistan’s prime minister Imran Khan expressed his anguish over the stoning, and said he was seeking a report from Punjab’s chief minister on the police handling of the case. He said they had “failed in their duty”.

“We have zero tolerance for anyone taking the law into their own hands and mob lynching will be dealt with with the full severity of the law,” Mr Khan said in a tweet hours after the incident.

The prime minister also asked the Punjab police chief for a report on the actions taken against perpetrators of the lynching.

The killing comes months after the lynching of a Sri Lankan manager of a sporting goods factory in Sialkot in Punjab province on December 3 who was accused by workers of blasphemy.

International and national rights groups say blasphemy accusations have often been used to intimidate religious minorities and settle personal scores. It is a crime punishable by death in Pakistan.