Young students sit in a room after being rescued in a police raid on a madrassa in Karachi late Monday.

Story highlights

Video shows young men and boys with heavy chains on their ankles

Police say it's not clear why the students were kept in such conditions

The school's imam was taken into custody for questioning

CNN  — 

Pakistani police rescued 54 men and 14 young boys Monday from an Islamic religious school and drug rehabilitation facility where they were found chained to one another and held in an underground room, police officials told CNN.

Video from the madrassa showed young men and boys – some appearing to be as young as 8 years old – with heavy chains connected to their ankles.

“Obviously there are good madrassas giving good education to good human beings, but there are others that are doing ugly things. We have to find out how this happened and take this issue very seriously,” Memon said.

Police said the students reported they were beaten and shocked with electric wires.

It was not immediately clear why the students were being kept in such conditions, or how long they had been there. The school’s imam was taken into custody for questioning, police said.

Speaking to GEO news, Gadap police official Rao Anwar said the majority of the children were from the Khyber Pakhtunkhwa region of Northwest Pakistan.

The students were enrolled in the madrassa by their parents to be religiously trained. Police said parents were unaware of the conditions their children were kept in.