Shafaq News/ Police north of Nigeria have rescued more than 300 young men from an Islamic boarding school where they have been chained and sexually assaulted, police said in the second such operation in a month.

The police team raided the school in Daura in Katsina state after some students fled the hostel on Sunday and went to the streets to protest against what the youths are facing at the school.

Katsina police Chief , Sanusi Buba told reporters in Daura that the youths had been chained and tortured.

"We have learned that the number of detainees here exceeds 300, and they revolted because of the inhumane treatment they are subjected to," he said.

"Some of them managed to escape while (60) remained inside," he said, adding that some of them were found chained.

Buba said the school was founded by a Muslim cleric, Blue Maay Almajirai, 40 years ago, and he later handed over the administration to his son.

He explained that the enrolled are students brought by their families to learn the Koran and receive treatment from drug addiction and other.

President, Mohamed Bahari comes from Daoura, 70 km (40 miles) from the state capital near Niger border.

The police official said that the students were from different parts of Nigeria and Niger.

According to Buba, the students were subjected to "inhumane conditions", some of whom revealed that their teacher "had sex with them."

He confirmed that the police will coordinate with the state government to verify their identities and communicate with their families to return them.

He pledged that the school official and its teachers who fled during the raid would be arrested and held accountable.

Last month, police in nearby Kaduna state freed more than 300 students from a boarding school who were similarly attacked.

High rates of drug addiction and the absence of rehabilitation centers in northern Nigeria are forcing parents to enroll their children in informal reform schools where they are abused.