Baghdad: US forces declared an area once known as the "triangle of death" safe enough for Iraqi troops to take charge on Thursday, handing over responsibility for security in Babil province to Iraqi forces.

The province south of Baghdad is the 12th of Iraq's 18 provinces in which primary responsibility for security has been given to Iraqi forces.

With violence at four-year lows, only the capital Baghdad, four ethnically and religiously mixed northern provinces and Wasit province along the Iranian border still require day-to-day US patrols of Iraqi streets.

Iraq's National Security adviser Mowaffaq Al Rubaie said at a handover ceremony in the provincial capital Hilla that Iraqis will also take control of Wasit province within days.

"This is proof that our military forces have reached self-sufficiency, and can now be depended upon to preserve internal security," Al Rubaie said.

Lieutenant-General Lloyd Austin, commander of US combat forces in Iraq, called the event a "milestone for Iraq in maturing as a sovereign and democratic nation."

"Just a year ago this province was experiencing well over 20 attacks per week. And today attacks are down well over 80 per cent. This is truly remarkable," he said. Iraqi troops, police and firemen then marched past to the sound of a brass band.

Babil, a vast province named for the ruins of ancient Babylon, includes rural Sunni Arab areas dotted with date palm groves along the Euphrates south of Baghdad, which US forces dubbed the "triangle of death" in years after the 2003 invasion.

The triangle was a heartland of the Sunni insurgency against US forces and the Shiite-led government in Baghdad until last year, when many Sunni Arabs joined US-funded patrols known as "Awakening" groups.

Babil's cities have also seen uprisings by followers of anti-American Shiite cleric Moqtada Al Sadr as recently as April this year. But they have been far quieter in recent months as Al Sadr's followers have held to a ceasefire.

Violence across Iraq has fallen over the past year to four-year lows, but militants are still able to carry out frequent car bomb and suicide bomb attacks. Suicide bombings are a signature tactic of Al Qaida militants.

Convoy hit: Minister survives blast

A suicide car bomber rammed into the convoy of Iraq's labour minister yesterday, killing 11 people and wounding 22, police said. A spokesman for the ministry said the minister, Mahmoud Al Shaikh Radhi, was unhurt. Three of his bodyguards were among the dead.

A Reuters television cameraman in the vicinity filmed the blast but an Iraqi soldier confiscated his videotape. The cameraman, about 150 metres away at the time of the explosion, saw a car slam into a convoy of six or seven four-wheel-drive vehicles and explode in a ball of flame near Tahrir square in central Baghdad. Police and bodyguards in the convoy opened fire after the blast.

- Reuters