Authorities in Liaoning province confirmed news reports that a drug-trading ring was operating inside a jail in the province's Tieling city, the Beijing News reported.

Drugs were found inside Tieling prison on Jan 17 after prisoners tipped off the prison administration after disputes over drug deals.

The Liaoning Prison Administrative Bureau confirmed on Wednesday that Tieling prison has uncovered a case in which former prisoners were selling drugs to prisoners.

Five prisoners who were involved in the case are being investigated, and police is trying to capture the former prisoners involved in the case.

No prison guards were involved in the case, the authority said.