BAGHDAD -- Radical cleric Muqtada Sadr on Sunday ordered his followers to lay down their weapons, offering Shiite Muslims a way out of six days of fighting that has left more than 350 people dead and exposed the weakness of Iraq's government and security forces.

Sadr demanded in a declaration broadcast from mosques in his Baghdad strongholds and across southern Iraq that the government in turn stop what he described as random raids and release his followers from detention.

Prime Minister Nouri Maliki welcomed Sadr's initiative as a "step in the right direction," and Baghdad authorities said an around-the-clock curfew here was lifted in most areas this morning.

Government aides vowed Sunday to press on with efforts to clear Basra of "outlaws" who have used violence to establish power and influence in the southern oil hub.

Maliki staked his reputation on the crackdown, which began Tuesday, vowing to remain in Basra until law and order was restored. But the campaign instead revealed the strength of Sadr's Mahdi Army militia, which fought more than 28,000 government troops to a standstill in parts of Basra and pounded Baghdad's fortified Green Zone with days of punishing rocket and mortar fire.

The government appeared to have misjudged the level of resistance it would face in Basra, or how quickly the fighting would spread, drawing in U.S. and British forces to provide air support and limited assistance on the ground.

Sadr's statement came after two senior Shiite lawmakers allied with Maliki sought a meeting with the cleric to negotiate a way out of the crisis.

"If anyone comes out a winner, it's Sadr," said Joost Hiltermann, Middle East director of the International Crisis Group. "He's coming out stronger, and Maliki looks like a lame duck."

Iraqi security and hospital officials said more than 350 people were killed as the fighting spread from Basra to parts of the capital, and other cities in the southern Shiite heartland.

Even after Sadr's declaration, residents hunkered down in their homes continued to hear fierce gunfire and explosions in central Basra and southwest of the city. A militia commander reached by phone in the city said his men would remain in the street.

"Of course we respect his eminence's initiative. However, the other side has to respect it too," said the fighter, who asked to be identified by a nickname, Abu Ahmed. "They are the ones who came to either arrest us or kill us unfairly."

The U.S. military said attacks had dropped off significantly in other parts of southern Iraq.

In Baghdad, sporadic gunfire and shelling continued into the night. The military said it had killed 25 "armed criminals" in an airstrike after a patrol was ambushed in east Baghdad with roadside bombs, rocket-propelled grenades, small arms and indirect fire, a military term for rockets or mortar rounds.

It was one of at least six airstrikes in Shiite-dominated parts of the capital Sunday that killed about 50 combatants, according to Maj. Mark Cheadle, a U.S. military spokesman.

Mahdi Army fighters in their vast east Baghdad stronghold of Sadr City handed out sweets to welcome Sadr's statement. Baghdad officials announced that though the curfew was being lifted, a driving ban remained in effect in Sadr City and two other Mahdi Army bastions.

The clashes have raised fears that a cease-fire declared by Sadr in August was unraveling, threatening to reverse the decrease in attacks since an American troop buildup reached its height in June.

Two U.S. service members died Sunday after roadside bombings, one north of Baghdad on Sunday and the other Saturday in Anbar province, west of the capital, the military said. At least 4,010 American military personnel have been killed since U.S.-led forces invaded in 2003, according to icasualties.org.

Before Sadr's announcement, one of Maliki's top security officials was killed in a mortar attack in Basra, according to a statement from the prime minister's Islamic Dawa Party. Gunmen also attacked a government television facility in the city, sending the guards fleeing and setting fire to several armored vehicles, police and residents said.

Sadr's order to stand down came in a nine-point declaration.

"Based on the responsibility imposed by Islamic law and to save precious Iraqi blood . . . we have decided the following: to end the armed manifestation in Basra and all over the governorates," Sadr said.