BAGHDAD (Reuters) - Two gay men were killed in Baghdad's Sadr City slum, a local official said on Saturday, and police said they had found the bodies of four more after clerics urged a crackdown on a perceived spread of homosexuality.

Homosexuality is prohibited almost everywhere in the Middle East, but conditions have become especially dangerous for gays and lesbians in Iraq since the rise of religious militias after U.S.-led forces toppled Saddam Hussein six years ago.

"Two young men were killed on Thursday. They were sexual deviants. Their tribes killed them to restore their family honor," a Sadr City official who declined to be named said.

The police source who declined to be named said the bodies of four gay men were unearthed in Sadr City on March 25, each bearing a sign reading "pervert" in Arabic on their chests.

Sermons condemning homosexuality were read at the last two Friday prayer gatherings in Sadr City, a sprawling Baghdad slum of some 2 million people. The slum is a bastion of support for fiery Shi'ite cleric Moqtada al-Sadr and his Mehdi Army militia.

The Mehdi Army has frozen its activities over the last year and government forces have wrested control of the slum.

Many young men who might have cut their hair short and grown beards when religious gangs controlled much of Iraq now dress in a more Western style as government forces take back control.

Some are now accused of being gay, and residents of Sadr City say at least one coffee shop has become a gay hangout.

A member of the slum's Sadrist office said the Mehdi Army was not involved in the killings, but said homosexuality was now more widespread since the Mehdi Army lost control of the slum.

"This (homosexuality) has spread because of the absence of the Mehdi Army, the spread of sexual films and satellite television and a lack of government surveillance," said the office's Sheikh Ibrahim al-Gharawi, a Shi'ite cleric.

Homosexual acts are punishable by up to seven years in prison in Iraq. A gay Iraqi man said any alleged crimes should be left to the law to deal with.

"If they've committed a crime, then there is the law. Killing is a big sin," he said, giving his name as Laith.