A bomber in a car has blown himself up outside Iraq's interior ministry in Baghdad, killing 16 people in a bloody challenge to the prime minister's assertions that violence is on the decrease.

Police sources put the toll at 16 with 35 wounded on Monday.

Interior ministry sources said at least 10 people were killed and 28 wounded, citing casualties from one hospital.

The attack came a day after a spate of car bombings and shootings across Iraq killed about 60 people as thousands of US and Iraqi troops pressed on with a major operation to control the capital.

Operation Together Forward is designed to root out fighters, ease sectarian violence and raise the credibility and profile of the Iraqi security forces, whose performance will determine when US troops leave.

Roadside bombs

Among those killed on Sunday, were four American soldiers hit by a single roadside bomb north of Baghdad, the US military said on Monday.

A roadside bomb, one of the most lethal weapons used by armed fighters seeking to topple the Shia-led government backed by Washington, also killed a US soldier in western Baghdad, the military said.

In a recorded interview with CNN on Sunday, Nuri al-Maliki, the prime minister, said violence was on the decrease and that the country would never slide into a civil war. He refused to be drawn on a timetable for a US withdrawal.

Clashes

Also on Monday, eight civilians were killed in clashes between militiamen loyal to Muqtada al-Sadr, a populist Shia figure, and Iraqi and US forces in the town of Diwaniya, south of Baghdad, a local official said.

Seven Iraqi soldiers were wounded, said an army source.

Eight civilians were killed and 70 wounded in the fighting which broke out on Sunday, the general director of the Diwaniya health directorate, Hamid Jaafi, said.

There was no immediate word from the US military.

Photo Caption

A man is treated in a nearby hospital after the attack