Gunmen killed a Shiite tribal sheikh linked to British forces in a drive-by shooting today in the southern city of Basra, while two US Marines were reported killed in fighting in a volatile province west of Baghdad.

In the deadliest attack since the beginning of the Iraq war, suspected Sunni-Arab militants used three suicide car bombs and two mortar rounds on the capital’s Shiite Sadr City slum to kill at least 145 people and wound 238 today, according to police.

IRAQI politicians were urged yesterday to speed up negotiations to form a new government.

Two Britons were killed and three injured today when gunmen attacked a bus carrying Muslim pilgrims south of Baghdad, police and hospital officials said.

Followers of radical cleric Muqtada al-Sadr trickled in to police stations in a Baghdad slum district to hand in weapons today under a deal seen as a key step toward ending weeks of fighting with US and Iraqi forces in the Shiite militant stronghold.