(Baghdad)  Militiamen are torturing and killing gay Iraqi men with impunity in a systematic campaign that has spread from Baghdad to several other cities, a prominent human rights group said in a report.

The bodies of several gay men were found in Baghdad’s main Shiite district of Sadr City earlier this year with the Arabic words for “pervert” and “puppy” – considered derogatory terms for homosexuals in Iraq – written on their chests.

The New York-based advocacy group said the threats and abuses have since spread to the cities of Kirkuk, Najaf and Basra, although the practice remains concentrated in the capital.

“Murders are committed with impunity, admonitory in intent, with corpses dumped in garbage or hung as warnings on the street,” the 67-page report said.

Reliable numbers weren’t available, Human Rights Watch said, blaming a combination of the failure of authorities to investigate such crimes and the stigma preventing families from reporting the deaths. But it cited a well-informed U.N. official as saying in April that the death toll was probably “in the hundreds.”

The campaign has been largely blamed on Shiite extremists who have long targeted behavior deemed un-Islamic, beating and even killing women for not wearing veils and bombing liquor stores.

Shiite militiamen have for the most part stopped their violence against rival Sunnis after radical cleric Muqtada al-Sadr’s forces were routed by U.S. and Iraqi forces last year and declared a cease-fire. But the report indicated they were conducting a less publicized campaign of social cleansing.

“The same thing that used to happen to Sunnis and Shiites is now happening to gays,” said a doctor who had fled Baghdad and was interviewed for the report. The doctor, who described himself as gay, said several of his friends had been killed.

An Iraqi Interior Ministry official, speaking on condition of anonymity because he wasn’t authorized to discuss the issue with the media, acknowledged there has been a sharp escalation in attacks against gay men this year by suspected Shiite extremists. But he told The Associated Press that the ministry does not have numbers “because in most cases the family members themselves are either involved in the killing or prefer to keep silent, fearing shame.”

The former No. 2 official at the U.S. Embassy in Iraq, Patricia Butenis, wrote in a letter to a U.S. congressman that reports from contacts familiar with the areas where some of the bodies were found “suggest the killings are the work of militias who believe homosexuality is a form of Western deviance that cannot be tolerated.”

The letter was in response to concerns raised by U.S. Rep. Jared Polis, a Colorado Democrat who is openly gay. Polis had brought up the issue during a visit to Iraq.

Homosexuals have been targeted throughout the Iraq war, but the killings appear to have intensified as improvements in overall security led gay men to begin going out to cafes in groups and socializing in public, according to the report.

Human Rights Watch accused authorities of doing nothing to stop the killings and warned that reflected an overall inability to protect the people.

“These killings point to the continuing and lethal failure of Iraq’s post-occupation authorities to establish the rule of law and protect their citizens,” said Rasha Moumneh, a researcher at Human Rights Watch.

The Human Rights Watch report was based on interviews with more than 50 Iraqi men who identified themselves as gay as well as Iraqi human rights activists, journalists and doctors.

The Iraqi government’s Human Rights Ministry has condemned the killings of gay men.

“We are against any violation of their rights because they are after all Iraqi citizens,” said ministry spokesman, Kalim Amin. “The government should not allow any armed group to launch random killings against people, sometimes only for mere suspicion.”

Sadr City, a teeming slum district, is a stronghold of al-Sadr’s militia, which launched several uprisings against American forces after the U.S.-led invasion in 2003 before U.S.-Iraqi forces seized control last year.

Iraqi police said homosexuals were afraid of being seen in public while the militiamen were in charge of Sadr City but began going out more as violence declined.

Fliers warning homosexuals that they will be killed “unless they come back to their senses” were distributed in Sadr City earlier this year and Shiite clerics have frequently called for the “education and rehabilitation” of gays in their Friday sermons.

Sadrist Sheik Ammar al-Saadi has denied any involvement by the movement in the killings and said the clerics only urged people to stop practicing homosexuality.

One 35-year-old man with the pseudonym Hamid has been unable to speak properly since his partner of 10 years was seized from his parents’ home in early April by four gunmen wearing black. His body was found the next day.

“They had thrown his corpse in the garbage. His genitals were cut off and a piece of his throat was ripped out,” Hamid was quoted as saying.

Human Rights Watch singled out the use of glue to seal men’s rectums as a common form of torture.

The report said Iraqi law does not ban consensual homosexual conduct between adults but contains certain provisions that can be exploited, including Saddam Hussein-era provisions that could reduce penalties for so-called honor crimes and crimes against people due to their sexual orientation.