Zimbabwe police have said they arrested a man claiming to be a prophet of an apostolic sect at a compound where more than 250 children were allegedly being used as cheap labour, and where authorities found 16 unregistered graves.

In a statement, police spokesperson Paul Nyathi alleged Ishmael Chokurongerwa, 56, a “self-styled” prophet, led a sect with more than 1,000 members at a farm about 34km (21 miles) north-west of the capital, Harare, where the children were staying alongside other believers.

The children, who have now been rescued, “were being used to perform various physical activities for the benefit of the sect’s leadership,” he alleged. Of the 251 children, 246 had no birth certificates.

“Police established that all children of school-going age did not attend formal education and were subjected to abuse as cheap labour, doing manual work in the name of being taught life skills,” Nyathi alleged.

Police said among the graves discovered were those of seven infants whose burials were not registered with authorities.

He said police officers raided the shrine on Tuesday. Chokurongerwa, who called himself the Prophet Ishmael, was arrested together with seven of his aides “for criminal activities which include abuse of minors”.

Nyathi said more details would be released “in due course as investigations unfold”.

A state-run tabloid, H-Metro, which accompanied police during the raid, showed police in riot gear arguing with female believers in white garments and head cloths who demanded the return of children who were put into a waiting police bus. It is not clear where police took the children, and some women who accompanied them.

“Why are they taking our children? We are comfortable here. We don’t have a problem here,” shouted one of the women in a video posted on the newspaper’s X, formerly Twitter, account.

According to the newspaper, police officers armed with guns, teargas and dogs “staged a spectacular raid” on the shrine. Believers described the compound as “their promised land”.

Apostolic groups that infuse traditional beliefs into a Pentecostal doctrine are popular in the deeply religious southern African country.

There has been little detailed research on Apostolic churches in Zimbabwe, but Unicef studies estimate it is the largest religious denomination with about 2.5 million followers in a country of 15 million. Some of the groups adhere to a doctrine demanding that followers avoid formal education for their children as well as medicines and medical care for members who must instead seek healing through their faith in prayer, holy water and anointed stones.

Others have in recent years begun allowing their members to visit hospitals and enrol children in school after intense campaigns by the government and non-governmental organisations.