Sexual abuse of young boys by mullahs is rampant at Islamic schools in Pakistan, an investigation has found.

Abuse is a pervasive and longstanding problem at educational establishments in Pakistan, an Associated Press investigation has found.

However, as religious clerics are powerful, the abuse is rarely discussed or acknowledged in public, according to alleged victims' families.

Kausar Parveen comforts her child who was allegedly raped by a mullah or religious cleric, in Kehror Pakka, Pakistan

A handcuffed Pakistani cleric who allegedly raped a child, stands outside a court in Kehror Pakka, Pakistan

Police are often paid off not to pursue justice against clerics, they add, and cases rarely make it past the courts, because Pakistan's legal system allows the victim's family to 'forgive' the offender and accept what is often referred to as 'blood money.'

When offending mullahs pay police off, they refuse to even register a case, according to the families.

'We are being pressured to compromise,' says a man from Punjab who would only give his name as Maqsood. His younger brother says he was sexually assaulted at a madrassa by a cleric who threatened to kill his family if he told.

Ms Parveen recounts the ordeal of her son during the emotional interview with Associated Press

A tally of cases reported in newspapers over the past 10 years of sexual abuse by maulvis or clerics and other religious officials came to 359. That represents 'barely the tip of the iceberg,' says Munizae Bano, executive director of Sahil, the organization that scours the newspapers.

Sahil offers families legal aid to pursue such cases. Last year, it found 56 cases of sexual assault involving religious clerics. Yet none of the families accepted Sahil's offer of legal assistance as they come under intense pressure to 'forgive' the crime or settle for money as they believe they do not have the power to do anything else.

Speaking in an emotional interview with Associated Press, Kausar Parveen wiped away tears as she spoke to her 9-year-old son about what happened when he was allegedly attacked by a cleric.

The youngster was visibly upset when he was asked and confirmed he was 'touched', 'hurt' and 'raped'.

In 2004, a Pakistani official disclosed more than 500 complaints of sexual assaults against young boys in madrassas. He has since refused to talk.

Two officials familiar with the educational establishments said sexual abuse there happens all the time. They asked to remain anonymous for fear of retribution from militant groups. One compared the situation to the abuse of children by priests in the Catholic Church.

A Pakistani boy who was allegedly raped by a mullah or religious cleric, sits on a swing

A Pakistani boy who was allegedly raped by a mullah or religious cleric, sits before villagers in Vehari, Pakistan

'There are thousands of incidences of sexual abuse in the madrassas,' he says. 'This thing is very common. ... I am not sure what it will take to expose the extent of it. It's very dangerous to even try.'

Religious Affairs Minister Sardar Muhammad Yousaf dismisses the suggestion that sexual abuse is widespread, saying such talk is an attempt to malign the religion, seminaries and clerics. He acknowledges that it could occur occasionally 'because there are criminals everywhere.'

More than 22,000 registered madrassas or Islamic schools in Pakistan teach at least 2 million students, often among the country's poorest, who receive food and an education for free. Thousands more madrassas are unregistered and operate without scrutiny, like the one attended by Ms Parveen's son.

Ms Parveen sits with her son as other villagers sit and watch on during the interview

Rana Mohammad Jamal talks about an alleged rape attempt on a girl by mullah or cleric in Kehror Pakka

The top police officer in the district center of Multan, Deputy Inspector General Police Sultan Azam Temuri, denies that pressure from clerics or powerful politicians prompts police to go easy in such cases. He says cases are investigated when allegations are made. Temuri says his department is trying to tackle child abuse in general with the introduction of gender and child protection services.

The Interior Ministry, which oversees madrassas, refused repeated written and telephone requests for an interview.