More than 300 men and boys have been rescued from a 'house of torture' Islamic boarding school where they were detained and raped by staff for years in Kaduna, Nigeria.

Many were found chained up and the detainees, mostly children, said they had been tortured, sexually abused, starved and prevented from leaving.

Police raided a building in the city on Thursday where the victims were kept in 'the most debasing and inhuman conditions in the name of teaching them the Koran and reforming them', a police spokesperson said.

More than 300 people have been freed from a 'house of torture' in Kaduna, Nigeria, where they were sexually abused and tortured

During the raid on the school, police said they found a 'torture chamber' where students were chained, hung and beaten

The school which has been operating for a decade, enrolled students brought by their families to learn the Koran and be rehabilitated from drug abuse and other illnesses

'They claim to be teaching us Quran and Islam, but they do a lot of things here. They subject the younger ones to homosexuality,' victim Bello Hanza said

They were pictured with horrific scars on their backs and with their hands and feet in chains after their release.

Kaduna state's chief of police Ali Janga said it was a case of 'human slavery' and they raided the house after an anonymous tip-off on Thursday.

He told the BBC it was a 'house of torture' with men and boys from Burkina Faso, Mali and other African countries.

Police said the detainees were from Burkina Faso, Mali and other African countries.

The victims, including adults and minors, were kept in 'the most debasing and inhuman conditions in the name of teaching them the Koran and reforming them', Kaduna state police spokesman Yakubu Sabo said.

The school, which has been operating for a decade, enrolled students brought by their families to learn the Koran and be rehabilitated from drug abuse and other illnesses, police said.

Some of the 300 male students of 'different nationalities' sit on the floor in chains outside the school's torture chamber in the Rigasa area of Kaduna in northern Nigeria

Many were found chained up and the detainees, mostly children, said they had been tortured, sexually abused, starved and prevented from leaving

The detainees, most of them young boys, emerged with scars on their bodies after police raided the building

The proprietor of the school and six staff were arrested during the raid but he insists he did nothing wrong

The proprietor of the school and six staff were arrested during the raid.

'We found around 100 students including children as young as nine, in chains stuffed in a small room, all in the name of reforming them and making them responsible persons,' Sabo said.

'The victims were abused. Some of them said they were sodomised by their teachers.'

Bello Hamza, 42, told The Nigerian Tribune: 'I have spent three months here with chains on my legs. I am supposed to be pursuing my Masters in University Pretoria South Africa. I got admission to study Applied Mathematics, but here I am chained.

'They claim to be teaching us Quran and Islam, but they do a lot of things here. They subject the younger ones to homosexuality.

'This is supposed to be an Islamic centre, but trying to run away from here attracts severe punishment; they tie people and hang them to the ceiling for that, but engaging in homosexuality attracts no punishment.'

He also said he has seen people die from the torture during his time there.

Police had been tipped off by complaints from local residents who became suspicious of what was happening inside the school.

During the raid on the school, police said they found a 'torture chamber' where students were chained, hung and beaten.

A look through the fence security wire reveals the inside of Daru Imam Ahmad Bun Hambal Islamic school in Kaduna, Nigeria

Authorities said the freed captives will be given medical and psychological examinations

Police who raided the building said the detainees were from Burkina Faso, Mali and other African countries

Sabo said the victims were of different nationalities and that 'two of them said during interrogation they were brought by their parents from Burkina Faso'.

The identities of the rescued victims were being documented to determine where they came from and to contact their families.

Parents of some of the victims from within the city, contacted by police were 'shocked and horrified' when they saw the condition of their children, as they had no idea what was happening inside the school.

Parents were allowed to visit their children every three months, but only in select areas of the premises.

'They were not allowed into the house to see what was happening... the children are only brought to them outside to meet them,' Sabo said.

'All they thought was their children are being taught the Koran and good manners as they looked subdued,' he added.

The owner of the school said all they do is teach people Islam and said the allegations of torture and sexual assault are false,

Police said the detainees were kept in 'the most debasing and inhuman conditions in the name of teaching them the Koran and reforming them'

A man stands with chains on his ankles and wrists. Private Islamic schools are common in mainly Muslim northern Nigeria, where government services are often lacking

Private Islamic schools are common in mainly Muslim northern Nigeria, where government services are often lacking.

The owner of the school said all they do is teach people Islam and said the allegations of torture and sexual assault are false, despite acknowledging people were in chains.

He said: 'They don't do anything other than recitation of Qur'an, pray and worship God.

'Those chained are the stubborn ones who attempt running away. Those who don't attempt running away are not chained. Some were chained before and after settling down, they were freed.'

They were taken to a stadium to be looked after while police make attempts to find their families.

Authorities said the freed captives will be given medical and psychological examinations.