Perverted ISIS militants are trying to score Viagra to fuel their lust for “brutal and abnormal” sex, according to a shocking report from activists in the terror group’s main Syrian stronghold.

The supposedly ultra-conservative Muslim fundamentalists have been forcing women in the city of Raqqa to marry them and engage in savage sex acts that result in hospital treatment, the report says.

The jihadists also buy kinky lingerie — described in the report as “strange underwear” — for their reluctant brides, according to the “Raqqa Is Being Slaughtered Silently” activist group.

“A large section of ISIS members suffer from sexual anomalies and brutal instinctive desire for sex,” the group wrote on its website.

Several families have reportedly fled the city — and one girl committed suicide — to avoid the lusty ISIS terrorists’ clutches.

ISIS overran Raqqa in 2013 and turned the northern Syrian city into its de facto capital, imposing harsh religious laws and publicly beheading and crucifying opponents in the ironically named Paradise Square.

In a related development, two British human rights groups on Wednesday said ISIS kidnapped at least 3,000 women and girls last year from the areas it controls in Iraq.

Some victims were forced to marry ISIS terrorists, while others were sold into sexual slavery, according to a report by Minority Rights Group International and the Ceasefire Centre for Civilian Rights.

The report said firsthand accounts from victims who spoke secretly by phone in August revealed that ISIS fighters were raping women on a daily basis, with some victims begging the activists to arrange airstrikes on their locations and end their suffering.

One kidnapped girl who belongs to the minority Yazidi religious group also said she was among 350 girls transported to Syria and offered for sale “as if in a chicken market.”

With Post Wires