Iraqi militants struck a U.S. base and an American convoy in separate attacks, killing three soldiers, the military said Sunday.

Militants continued to attack U.S. forces in Iraq, killing one soldier and wounding 10 in a bombing and shooting attack on a coalition base near the northern Iraqi city of Kirkuk (search).

The wounded were evacuated to a nearby medical facility, the U.S. military said. No further details were released.

A convoy was attacked Saturday evening outside the city of Amarah, 180 miles south of the capital, when gunmen loyal to radical Shiite cleric Muqtada al-Sadr opened fire with small arms and rocket-propelled grenades, a U.S. military official said.

A number of Humvees and trucks were seen burning on the road hours later, witnesses said.

British forces battled al-Sadr's al-Mahdi Army militia for 12 hours in Amarah in fighting that left five Iraqis dead and eight British soldiers wounded.

The clash began when gunmen attacked a British patrol, wounding one soldier. Five more soldiers were wounded as a team rescued the first man, said British Royal Air Force Squadron Leader Jonathan Arnold.

Fighting revived in the evening when insurgents fired mortar shells and rocket-propelled grenades at the British base in the city, and British soldiers lobbed flares into the night sky and fired on attackers.

Two more British soldiers were wounded, and witnesses said two British trucks were burned. An Iraqi civilian working on the base was wounded by shrapnel from an exploding mortar shell, the British military said.

Two more American soldiers were killed before dawn Sunday in an attack in northwest Baghdad that also wounded two Iraqi security officers and another American, the military said without elaborating.

The killing raised the U.S. death toll to 145 since a wave of violence that began April 1. At least 747 U.S. troops have died in Iraq since the war began in March 2003.

Meanwhile, Marines who pulled back from enforcing a cordon on the southern city of Fallujah returned to their previous duties patrolling outlying villages, giving way to a newly created Iraqi brigade that the Americans said would root out die-hard guerrillas in the Sunni militant stronghold.

The new "Fallujah Brigade," put together by former Saddam Hussein-era generals, likely will include some former army soldiers who fought Marines during the past month, U.S. Marine Lt. Gen. James Conway said.

Conway insisted that the U.S. withdrawal did not mean a letup in the pursuit of the guerrillas.

"They understand our view that these people must be killed or captured," Conway said. "They have not flinched. And their commander has said as much to his assembly of officers."

The Fallujah Brigade, led by former Republican Guard member Maj. Gen. Jassim Mohammed Saleh, fanned out and imposed a cordon around nearly the entire southern half of Fallujah.

If all goes well there, the Iraqi force will next replace Marines in the north within a few days, a U.S. official said on condition of anonymity.

Scores of Iraqis gathered in the streets Saturday, some flashing V-for-victory signs and raising the Iraqi flag. Motorists drove through the streets, shouting, "Islam, it's your day!" and "We redeem Islam with our blood!"

The U.S. base in Najaf, meanwhile, came under mortar fire Sunday, despite claims by mediators that the al-Mahdi Army agreed to a truce supposed to last through the day. There were no casualties from the mortar fire, U.S. officials said.

Still, al-Sadr appeared to be looking for a way to end his confrontation with U.S. forces while avoiding arrest, mediators said.

Najaf's police chief, Ali al-Yasser, was seeking to meet U.S. officials Sunday to present a five-point proposal, the mediators said.

But the top coalition official in Najaf, Phil Kosnett, insisted al-Sadr must "face justice" and said there were no plans for a Sunday meeting.

"The coalition is not negotiating with anyone on any five-point plan," he said, though the coalition "meets with local officials every day to discuss the situation."

The plan, put together by tribal leaders after talks with the Najaf police chief, calls for the al-Mahdi Army to leave Najaf and for al-Sadr not to be jailed on a murder charge until a new government is formed, said tribal leader Hakem al-Shibli, a negotiating team member.

He said Najaf's tribes would reject any American demand to arrest al-Sadr, who is wanted for alleged involvement in the slaying of a rival cleric last year.

"If the Americans insist on it, despite the compromises that Seyed Muqtada has made, it would not be just," al-Shibli said.

The mediators — made up of tribesmen and a former judge — received the blessing of the office of Grand Ayatollah Ali al-Husseini al-Sistani, Iraq's most senior and influential Shiite cleric, al-Shibli said.

However, an al-Sadr spokesman who met with the mediators Saturday, Sheik Qais al-Khazali, was less optimistic, saying Americans were responsible for the failed efforts. If the Americans rejected a peaceful settlement, the al-Mahdi Army would fight, he said.

"All the political attempts to reach a peaceful settlement have failed. We prefer negotiations and want to avoid bloodshed," al-Khazali said.

Hundreds of U.S. troops are deployed outside the Najaf-Kufa area, and a contingent has moved into a base within the city, about three miles from sensitive holy sites in Najaf. The Americans have clashed occasionally with al-Sadr followers outside the city.

The U.S. military moved to capture al-Sadr after his militia staged an uprising across the south, sparked by the arrest of an aide. That uprising has died down, but his militiamen still dominate Najaf, Kufa and Karbala, the three holiest Shiite cities in Iraq.