Pakistani police who raided an Islamic seminary where parents paid for their children to be treated for drug addiction have uncovered dozens of young people held in chains in a dirty basement.
Police involved in the Monday night rescue, which reportedly came after a tip-off, said an administrator at the seminary was arrested during the raid.
The parents of 53 young inmates at the seminary in Karachi paid to have their children treated with a regimen of Islamic instruction and worship.
"They were kept there like animals,'' Akram Naeem, a police officer, said. He added that students who tried to escape or were dealing drugs were chained together.
Former students including an eight-year-old told the AFP news agency that they were regularly beaten at the school, which was equipped with chains, hooks and a warren of basement rooms.
Police said 21 teenagers were among those found during the raid.
Naeem said officers had ruled out any possibility that the seminary had links with armed groups, which are known to use madrassas for recruitment.
Hanif Jullandhri, head of a federation of Pakistani madrassas, told Express television that the premises was not registered.
"We strongly condemn this and urge the government to take the harshest possible action against its owners. The government should investigate how such torture cells are established and operated," he said.
Azmat Ullah, a 17-year-old student, said his father sent him there because he suffered "fits" and could be violent.
"My father took me to several spiritual healers who said I was a victim of black magic," he told the AFP. "Three months ago, I was admitted here."
"My father pays 3,000 rupees [$34] per month to the madrassa as a fee to make me a normal person, but I still suffer from fits and despite that they kept me chained and beat me with sticks ruthlessly," Ullah added.
Another parent Mohammad Ashraf said he had sent his eight-year-old son Mushtaq Ahmed to the madrassa believing he would receive a religious education.
"I didn't know the madrassa management would beat him so mercilessly. I will no longer keep my son in this madrassa," he said.
His son said the teachers beat the students daily.
There is little or no state help for drug addicts in Pakistan, and other seminaries in the country offer similar treatment.
Many institutions in Pakistan are also known to chain addicts and some mental patients.
Pakistan has thousands of unregulated seminaries offering free or cheap education, food and lodging for poor children. Reports of abuse at such centres occasionally surface.
An estimated 1.7 million Pakistani children, or five per cent of all those in formal schooling, are educated at Islamic seminaries.
Video footage taken after the raid showed men in chains and the grubby basement room where they were held, along with bedding. The men had no obvious signs of mistreatment.
Several parents, who paid the seminary around $150 to take their children, protested the raid at a local police station.
"I brought my grown up son here because he is a drug addict and he was making my life miserable,'' one man told a local television station. "I don't want to take him back.''