US forces stormed the home of rebel Iraqi Shi'ite cleric Moqtada al-Sadr in the holy city of Najaf today, witnesses said.
They said servicemen went into the house in the centre of the city after warplanes bombed nearby targets and battled militiamen loyal to Sadr. The cleric was believed to be at Imam Ali shrine, some two km away.
A fire was still raging in the street when Humvees drove to the house.
US marines, backed by aircraft, swooped on Najaf's city centre earlier in an attempt to end week-long fighting with Sadr's militiamen. But they stayed away from Imam Ali Mosque, one of the holiest sites in Shi'ite Islam.
US marines took control of the city centre after a major assault today and are blocking roads to the holy shrine.
An official from Sadr's Mehdi Army had warned that militiamen would blow up pipelines in the south if US forces tried to storm their Najaf bases.
Warplanes and helicopter gunships pounded the outskirts of Najaf's cemetery today, and gunmen responded by firing rocket-propelled grenades and mortar bombs at US positions, witnesses said.
Most of Sadr's men and the young Muslim cleric himself are hidden around Najaf's ancient Shia cemetery or the adjoining Imam Ali Shrine. Storming such holy symbols could spark a major reaction among Iraq's majority Shia community.
Thousands of Sadr's supporters vented their anger against interim Prime Minister Iyad Allawi in the streets of Nassiriya and several other cities yesterday.
US forces say they have killed 360 Sadr loyalists so far in Najaf, home to 600,000 people and some 160 kilometres south of Baghdad. Sadr's spokesmen say far fewer have died in what is the second rebellion by the militia in four months.