Fiery Muslim cleric Moqtada al Sadr appeared in public for the first time in months yesterday to renew demands for the withdrawal of US forces from Iraq and to paint himself as a leader for all Iraqis.

About the time he was delivering a sermon in the holy city of Kufa, British and Iraqi special forces killed a top leader of his feared Mehdi Army militia in southern Basra.

Al Sadr had not been seen since a security crackdown began in February, but the charismatic Shi'ite cleric re-emerged to brand the United States, Britain and Israel the "evil trio".

In his sermon, al Sadr sought to portray himself as a national leader prepared to defend the interests of Sunni Muslims and Christians as well as majority Shi'ites.

"I renew my demand for the occupiers to leave or to draw up a timetable for withdrawal, and I ask the government not to let the occupiers extend their occupation even for one day," Sadr told worshippers.

The US military says al Sadr fled to Iran in January before the security plan was launched, but aides insist he never left Iraq.

"Now that he's back from four months in Iran, we hope he'll play a constructive role in the future of Iraq," White House National Security Council spokesman Gordon Johndroe said in Washington.

Al Sadr's Mehdi Army militia fought two pitched battles against US troops in 2004.

His reappearance comes at a crucial time for Prime Minister Nuri al Maliki's Shi'ite-led government, which is under pressure from Washington to meet targets for promoting national reconciliation.

Six Sadrist ministers withdrew from Maliki's government last month in protest at the prime minister's refusal to set a timetable for a US troop withdrawal.

In southern Basra, the British military said Iraqi special forces had killed the leader of al Sadr's militia.

Wissam Abdul Qader and at least one aide were shot shortly after leaving Sadr's office in the city centre.

British military spokesman Major David Gell said Abdul Qader resisted arrest. He was suspected of involvement in planting roadside bombs, weapons trafficking, assassinations and planning and participating in attacks against British troops.

British troops have stepped up operations against Shi'ite militias as they prepare to hand Basra over to Iraqi security forces later this year.

The US military has deployed thousands of extra troops around Baghdad and other areas in a last-ditch attempt to drag Iraq back from the brink of all-out sectarian civil war between majority Shi'ites and Sunni Arabs dominant under Saddam Hussein.

The US military announced the deaths of six more soldiers in Iraq, underscoring George W Bush's prediction a day earlier that a bloody summer lay ahead. Ninety US soldiers have been killed this month.

In Washington, Republican and Democratic congressional leaders both forecast a change in Bush's Iraq war policy as the president prepared to sign legislation providing funds for US military operations until September 30.

"I think the president's policy is going to begin to unravel now," said the Democratic leader of the House of Representatives, Speaker Nancy Pelosi. She described the newly-passed measure as a disappointment because it did not force an end to US participation in the conflict.

Senate Republican Leader Mitch McConnell predicted a change in the autumn and said Bush would show the way.

The legislation, passed late on Thursday, ended a power struggle in which Bush rejected an earlier bill that contained a troop withdrawal timetable.

The war spending bill provides about £48bn for the wars in Iraq and Afghanistan.

-AP