BAGHDAD - A shaky cease-fire appeared to take hold Tuesday in Baghdad's Sadr City, after a cleric who brokered the deal for Shiite fighters said they would honor it even after clashes left at least 11 dead and 19 wounded.

The pact was intended to stop seven weeks of fighting between U.S.-supported Iraqi troops and Shiite extremists who have fired more than 1,000 mortars and rockets into the Green Zone, home to the government and Western embassies. But the cease-fire did not start well, with clashes late Monday and early Tuesday.

Iraqi medics reported 11 killed and 19 wounded. The U.S. military said Tuesday that it could confirm the deaths of six militants.

A U.S. soldier was killed just before dark Tuesday when a roadside bomb exploded next to his vehicle in northwest Baghdad, the military said. At least 4,077 U.S. military personnel have died since the war began in March 2003, according to The Associated Press.

The Sadr City fighting and cease-fire have brought into question the authority of anti-American cleric Muqtada al-Sadr, who currently lives in Iran. Al-Sadr signed a cease-fire agreement in August, but Shiite militiamen have recently ignored those orders.

Lt. Col. Steve Stover, a military spokesman for American troops in Baghdad, said Tuesday that the fighting was caused by Shiite factions that have broken with al-Sadr. Many are thought to be trained and armed by Iranian forces. Iran denies the allegations.

Nevertheless, pro-Sadr clerics negotiated the new cease-fire, and one said Tuesday that it was taking hold and would be enforced.

"We signed an agreement, and we are loyal to the agreement we reached," said Sheik Salah al-Obeidi, an aide to al-Sadr. "There might be some violations from both sides, and we have to try to prevent them."

The deal allows Iraqi forces to take over security today in Sadr City, the stronghold of al-Sadr's Mahdi Army militia.