U.S. troops patrolling in Sadr City, Baghdad's densely populated Shiite Muslim slum, were attacked Friday with automatic-rifle fire, rocket-propelled grenades, mortars and hidden explosives. Five American soldiers were killed and five wounded in the deadliest of three clashes.

The attacks in the capital, which brought the number of U.S. combat deaths in Iraq to 601, coincided with hopes of a cease-fire between Shiite militia fighters and U.S. forces in the Najaf area, 90 miles to the south. The Baghdad fighting was a reminder of the violence that continues here while diplomats make plans at the United Nations for turning over limited authority to an interim government June 30 and restoring momentum to the flagging international reconstruction effort.

A U.S. military spokeswoman said the first attack occurred in the early morning, with mortar rounds and rocket-propelled grenades hitting a police station where U.S. soldiers were stationed. Local residents said three Iraqis were killed in the ensuing gun battle.

Later in the morning, U.S. military vehicles came under fire from rocket-propelled grenades and automatic rifles. U.S. soldiers returned fire, the spokeswoman said, but there were no known casualties. Shortly after muezzins called the faithful to Friday's midday prayer in the strongly Muslim neighborhood, a roadside explosive detonated as U.S. troops in Humvees drove by, killing five Americans and wounding five, she reported.

Prime Minister Ayad Allawi, in his first address to the nation, called on Iraqis to rise up against the insurgents responsible for such attacks, calling them terrorists and aggressors, and promised his countrymen that the United States and its allies would genuinely give back Iraq's sovereignty on June 30.

Reading dryly from a text, Allawi declared that Iraqis cannot accept foreign occupation but added that the 138,000 U.S. troops and their allies must remain for a time to impose order.

"Targeting the multinational forces of the United Nations, which are led by the United States, with the aim of expelling them from Iraq will inflict a major catastrophe in the country, especially if that happened before Iraq completes the rebuilding of its security and military institutions," Allawi said, referring to the insurgents' aim of driving out foreign forces.

"Let us all be one hand, act as one man, with our heads held high, to defeat terrorism and terrorists," he said. "This is the duty of all Iraqis, and I call on you to firmly confront these murderers and criminals and to cooperate with the public services to wipe out those evil forces."

But the task facing Allawi -- and by extension the Bush administration -- was evident in a statement issued by Moqtada Sadr, a Shiite cleric whose militia, known as the Mahdi Army, is confronting U.S. troops in Najaf and other southern cities. Sadr rejected Allawi's four-day-old government, saying it is illegitimate because it was "appointed by the occupier."

"There is no freedom or democracy without independence," said Sheik Jader Khafaji, reading Sadr's statement during Friday prayers at the mosque where Sadr often preaches in Kufa, which adjoins Najaf.

Sadr's tough stand contrasted with that of Grand Ayatollah Ali Sistani, the country's preeminent Shiite cleric, who on Thursday offered qualified support for the interim administration. Allawi, a Shiite Muslim who organized an exile group funded by the CIA before the war, went out of his way in the televised speech to thank Sistani and other "revered religious authorities."

Sistani also insisted that Iraq must regain genuine sovereignty, including control of military affairs. In that, he joined the main demand put forth by Sadr, his younger, more aggressive fellow Shiite cleric. The coincidence of their views, in a country with a 60 percent Shiite majority, suggests that the Bush administration will have a difficult time reconciling the promise of full sovereignty with its demand for continued U.S. command over all occupation troops.

Sadr's followers in particular -- in Sadr City as well as in Najaf and Kufa -- have shown little inclination to embrace U.S. plans for continuing to play a major political and military role in Iraq after the formal transfer of authority. For them, Allawi's new administration, like the Governing Council before it, is nothing more than an instrument of U.S. control.

"If the new government wants to show its good intentions, it should demand [that the] occupation . . . pull out from Iraq; this is the demand of all Iraqis," declared Nassir Saedi in a sermon at the Hikma Mosque in Sadr City, not far from where the U.S. military vehicles were attacked. He added: "The case is not a Sadr case, or a Mahdi Army case. It is a general case. Defense does not need a fatwa. The assignment is general. We must fight."

Despite the clashes and tough talk in Baghdad, the Najaf governor, Adnan Zurufi, announced that Sadr's militia and U.S. forces in the area had agreed to renew a cease-fire they reached eight days ago but never really abided by. Because the agreement essentially was a reiteration of the first truce, it was impossible to tell whether fighting in the Najaf and Kufa area would really subside.

A U.S. commander in Najaf, Col. Brad May, told a CNN correspondent there that the deal calls for U.S. forces to pull back from positions near Shiite shrines in Najaf and make room for Iraqi police, who would patrol the streets. Ahmed Shaibani, a Sadr spokesman in Najaf, said that in return, Sadr's fighters were withdrawing from any visible armed presence in Najaf and Kufa.

"We will withdraw the Mahdi Army from these cities if the Americans withdraw their forces," he declared.

Ahmed Chalabi, an exile politician and former Washington favorite now accused of revealing U.S. secrets to Iran, walked Najaf's streets Friday evening to dramatize the new accord and predicted that security will swiftly return to the city and its shrines, revered by Shiite Muslims. Chalabi was among the Shiite political and religious figures involved in renegotiating the cease-fire.

"You will witness the improvement of security in the coming few days," he told reporters.

The U.S. military announced, meanwhile, that last Sunday Iraqi police captured a man described by a U.S. spokesman as "a known terrorist and murder suspect." The man, identified as Omar Baziyani, was an associate of Abu Musab Zarqawi, a Jordanian blamed by U.S. authorities for attacks on American soldiers here, according to a statement.

"Baziyani remains in detention and is providing information to coalition forces," the statement said. "His capture removes one of Zarqawi's most valuable officers from his network."

The statement did not explain how or where Baziyani was captured or why it took five days to announce that he was in custody.

U.S. soldiers stand over an unidentified body after an attack on an Army patrol in Baghdad. Efforts continued to restore a cease-fire in Najaf area.