Islamabad: A custodian of a Sufi shrine in Pakistan's Punjab province killed at least 20 people in an apparent ritual killing in Saturday night, a district administration official said.

The attack occurred in Sargodha. The custodian, Abdul Waheed, and four others were arrested.

"Abdul Waheed used club and knife to kill these people visiting the shrine. He has confessed that he killed the victims," said Deputy Commissioner Liaquat Ali Chatta.

He said an injured woman had fled the scene and informed hospital staff of the attack.

Abdul Waheed is said have tortured devotees in an apparent effort to heal them.

Killings have been reported during exorcism rituals at some shrines in the past, but such a mass killing is unusual.

Millions of Pakistanis follow Sufism, a mystic branch of Islam overtaken recently by more conservative and hard-line versions of the faith.

Militant groups, including the Islamic State, have recently carried out attacks on Sufi shrines, including a suicide blast in February in Sehwan, in Sindh province. The explosion, which targeted the famous Lal Shahbaz Qalandar shrine, killed more than 70 people.

Pakistani news channels showed bewildered villagers standing in front of the shrine. News reports said police have started an investigation at the instruction of Chief Minister Shahbaz Sharif, brother of Prime Minister Nawaz Sharif.

According to televised reports, Abdul Waheed drugged devotees and then called them one by one to his room, where they were killed with a club and knife.

An elderly woman, who was identified only as Kishwar and lay on a hospital bed with a deep cut on the left side of her face, told the news channel Dunya, "I don't know what happened to the custodian of the shrine. He started beating and killing the devotees. He and some others ... beat us badly with clubs."

The Washington Post