BAGHDAD,(Reuters) – Up to nine people were killed in clashes between U.S.-led troops and the Mehdi Army militia of Shi’ite cleric Moqtada al-Sadr in eastern Baghdad early on Friday, police and witnesses said.

Aides to Sadr accused the security forces of killing innocent civilians and said some of the victims had been mourners in a funeral tent.

An Interior Ministry source said the fighting erupted when U.S. and Iraqi forces backed by helicopters raided houses in the slum district of Sadr City, a stronghold of Sadr’s Mehdi Army at 2 a.m. (2200 GMT).

He said the target of the raid was a senior Mehdi Army leader accused of masterminding a number of kidnappings.

It was not immediately clear whether the operation was linked to the abduction last week of a Sunni lawmaker. U.S.-led forces have launched a major operation to find her, while some Sunni leaders have blamed Shi’ite militias for her kidnapping.

The Interior Ministry source said nine people were killed and 31 wounded. Four houses were also destroyed. A police source put the death toll at seven and said the casualties were all militiamen.

The U.S. military said in a statement the raid had been by Iraqi soldiers, aimed at capturing an insurgent leader responsible for numerous deaths.

“The forces were immediately engaged by insurgents and a firefight ensued,” the military said in a statement, adding that no Iraqi or U.S. troops had been wounded or killed in the operation.

Sadr’s followers staged two revolts against U.S. and Iraqi troops in 2004, but the young cleric has since joined the U.S.- backed political process. His supporters now control key ministries in the Shi’ite Islamist-led government of Prime Minister Nuri al-Maliki.

Maliki, seeking to end sectarian violence and a Sunni insurgency, has unveiled a national reconciliation plan, which he promoted on a tour of Iraq’s Sunni Arab Gulf neighbours this week.

“Is this the gift of the prime minister when he has just returned from his trip?” Sadr aide Jalil al-Nuri said.

“The occupation forces place no value on the lives of civilians in Sadr City.”

Analysts say the strength of militias like Sadr’s Mehdi Army poses a growing threat to Maliki’s government, which Washington sees as the best hope of averting a slide to civil war.

The militias have grown in strength as Iraqi and U.S. security forces struggle to contain the violence which has killed tens of thousands since the U.S.-led invasion in 2003.