US aircraft bombed and razed  the office of radical Shia leader Muqtada al-Sadr in Baghdad early Monday morning, report agencies.

Witnesses saw a US aircraft drop at least one bomb on the single-storey structure, destroying it completely.  No casualties were reported.

Sadr is said to be in the Shia stronghold of Najaf, where fiece fighting was reported since Sunday morning.

The bombing came after Sadr's Mahdi militia  took over parts of the giant Sadr City slum in Baghdad yesterday, seizing control of police, municipal administration and schools and blocking freedom of movement in an area that is home to about a third of the city's 5 million residents, said The Washington Post.

The US military did not comment on the bombing, but reported 19 members of al-Sadr's Mahdi Army were killed in a series of clashes in the neighbourhood on Sunday.

On Monday, a South African engineer and a Iraqi driver were killed and a New Zealander seriously wounded when gunmen opened fire on their vehicle in Kirkuk, 250km north of Baghdad.

Also Monday, a US military convoy entered the restive Sunni stronghold of Fallujah for the first time in a month following a tenatative peace accord . Accompanying the Americans were Iraqi forces expected to administer the town which has seen some of the most intense fighting since US President George W. Bush declared an end to major combat in the country last May.

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