Relatives mourn near the lifeless body of a close family member of Khadim Sarhid al-Hemaiyem, in Baghdad, Iraq, Wednesday, Nov. 23, 2005

Authorities in Iraq say unidentified gunmen have killed a Sunni Arab tribal chief, three of his sons and a close relative.

Officials say they suspect insurgents, dressed in Iraqi army uniforms and driving army-type vehicles, broke into the home of the Batta tribal chief, Sheikh Khadim Sarhid on the outskirts of Baghdad early on Wednesday.

Elsewhere, the U.S. military says American and Iraqi forces began a new operation in the western city of Ramadi Tuesday.

It is the third offensive against insurgents in the area over the past seven days.

The military said earlier that US and Iraqi forces have ended a 17-day counter-insurgency offensive, Operation Steel Curtain near the Syrian border.

It said that operation, which marked the first large-scale deployment of the new Iraqi Army, was aimed at establishing a permanent Iraqi security presence in the region and improving conditions before December 15 elections.