Iraq's government has raised the death toll from a shooting involving US security contractor Blackwater to 17, from 11 previously.
A spokesman accused the firm of "deliberate killing" and said its guards fired without provocation.
An committee set up by Prime Minister Nuri al-Maliki had found no evidence Blackwater guards had come under fire during a September 16th shooting in west Baghdad, a government spokesman said.
He said Blackwater guards had "violated rules governing the use of force".
Blackwater has said its guards responded lawfully to an attack on a US State Department convoy.
The incident provoked outrage among Iraqis who see private security firms like Blackwater, which protects US diplomats in Baghdad, as private armies that act with impunity.
The US embassy said a joint US-Iraqi committee reviewing diplomatic security after the shooting had met for the first time yesterday.
The US military, which has poured 30,000 extra soldiers into Iraq to try to stem the sectarian warfare between Iraq's majority Shia and minority Sunni Arabs, says the troop "surge" has helped reduce some of the killing.
Eight people were killed in three bombings in Baghdad yesterday.