Baghdad, Iraq ? U.S. troops pounded Fallujah with airstrikes and tank fire Sunday, and the Iraqi government appealed to residents to expel “foreign terrorists” to prevent an all-out attack. A suicide driver in Baghdad exploded a car near a police patrol, killing at least seven people and wounding 20.

A mortar shell also exploded at a Baghdad sports stadium minutes before interim Prime Minister Ayad Allawi arrived to inspect a cash-for-weapons program for Shiite fighters. Insurgents, meanwhile, ambushed and killed nine Iraqi policemen as they were returning home from a training course in Jordan.

Throughout the day, the crackle of automatic weapons fire and the thud of artillery echoed across Fallujah, 40 miles west of Baghdad, as fighting between American troops and insurgents raged on the eastern and southern edges of the city, witnesses said.

U.S. Marines said Sunday that they used small arms, tanks, artillery, mortars and seven precision airstrikes against Fallujah insurgents. The Marines said that insurgents were seen taking refuge in a mosque but that troops did not fire on them.

American forces have stepped up attacks in the Fallujah area since peace talks between the Iraqi government and Fallujah clerics broke down after city leaders rejected Allawi’s demand to hand over “foreign terrorists,” including the Jordanian-born al-Zarqawi.

Fallujah clerics insist al-Zarqawi, whose Tawhid and Jihad movement has claimed responsibility for multiple suicide car-bombings and hostage beheadings, is not in the city. Fallujah fell under the control of hard-line Islamic clerics and their armed followers after U.S. Marines lifted a three-week siege in late April.

Despite the claim that al-Zarqawi is not in the city, a statement posted on an Islamic militant Web site on Sunday made a rare announcement that a member of Tawhid and Jihad identified as Sheik Abu Hafs al-Libi was killed fighting the Americans in Fallujah. The claim’s authenticity could not be confirmed.

As the Iraqis try to reach a peaceful end to the Fallujah standoff, the U.S. military is believed to be drafting plans for an all-out assault on the city if negotiations fail.

In London, the British Defense Ministry said the United States has asked Britain to redeploy hundreds of troops from southern Iraq amid reports the soldiers will back up the Americans in the event of a major attack on Fallujah.

British media reports say the United States wants British soldiers to replace units of the 2nd Battalion, 24th Marines in Iskandariyah, about 30 miles south of Baghdad.

Britain also was the site Sunday of an anti-war protest, where at least 15,000 anti-globalization advocates marched through central London and filled Trafalgar Square to protest the U.S.-led coalition’s presence in Iraq.