Captain Rogelio Maynulet, 30, was charged with murdering the man on May 21 in an incident during which US troops fired at a civilian vehicle they believed had militia men aboard near the central Iraqi town of Kufa.

The military spokesman said Maynulet was found not guilty of assault with the intent to commit murder by a military court martial panel sitting in Wiesbaden, western Germany.

Under US troop rules of engagement in Iraq, shooting at suspect cars is allowed under certain circumstances. Two men were in the vehicle. The passenger died instantly and the driver was badly injured.

Maynulet, who had pleaded not guilty to the charges, told the court martial that he had shot dead the driver from close range because he believed the man would not have survived his injuries.

The spokesman said that it was not immediately clear when the officer, who could face 10 years in prison, would be sentenced.