Abuja, Sep 27 (IANS): many in chains, from a building in the Kaduna city where they were detained and allegedly tortured, the media reported.
Those rescued were all men and boys. Kaduna state's police chief Ali Janga told the BBC that a large house was raided following a tip-off about suspicious activity.
The police official said it was a "house of torture" and described it as a case involving human slavery.
The detainees, not all Nigerian, said they had been tortured, sexually abused, starved and prevented from leaving -- in some cases for several years, the report said.
Some of the children told the police that their relatives had taken them there believing the building to be a "Koranic school". But the police said there was no concrete evidence to suggest that the building was ever a school.
Eight suspects have been arrested.