In a new initiative to avoid bloodshed in some of Islam's holiest places, a high-level delegation of Iraqi political leaders has been dispatched to the embattled city of Najaf to convince Shiite cleric Moqtada Sadr to abandon his violent rebellion and join the country's political process.

A political conference of more than 1,100 Iraqis -- originally convened to select a national assembly -- authorized the delegation Monday amid impassioned denunciations of Sadr's use of holy shrines as refuges for his militia and condemnation of the very existence of armed militias themselves in the new Iraq.

"The presence of an armed militia means there is a state within a state and this won't work," said a statement of principles approved by the conference Monday. "The religious shrines are not the personal property of anyone."

While the conference has received word that Sadr will meet with the delegation, some of its members voiced doubts that the rebellious cleric would come to terms, noting that he has reneged on previous agreements repeatedly.

Indeed, fighting resumed Sunday in Najaf after an earlier attempt at negotiations and a cease-fire collapsed. Two U.S. soldiers were killed, the military announced, and a Marine was killed in Iraq's western, largely Sunni province of Anbar.

But recalcitrance by Sadr under the new circumstances, many believe, could strengthen the hand of interim Prime Minister Ayad Allawi if he chooses to again authorize the use of force to remove Sadr's Mahdi Army from the shrines of Najaf, which are now cordoned by U.S. and Iraqi forces.

On Monday, U.S. tanks rolled to within 500 yards of the shrine of Ali, where the militants are hiding in the old city of Najaf, the Associated Press reported. The city was also hit by a series of explosions in the late morning that shook the vast cemetery adjoining the shrine, the scene of many battles between U.S. forces and militants.

The political conference here is a milestone in the country's transition to democracy. Convened Sunday, it was roiled at the outset by a dispute over the planned use of military force to confront militiamen loyal to Sadr.

In a remarkable scene of political activism that would have been unimaginable under Baath Party rule, dozens of Shiite delegates Sunday jumped to their feet in a loud protest of the interim government's decision to mount military operations to evict Sadr's followers from the shrine in Najaf. Chanting "Yes to Najaf!" and raising their fists, the Shiite dissenters demanded that the participants call on the interim prime minister and Sadr's followers to refrain from violence and for a special committee of delegates to negotiate a solution to the crisis.

The outburst triggered a succession of events that quickly reshaped government policy toward Najaf and instilled the first measure of checks-and-balances in Iraq's nascent political system.

On Sunday, the Shiite protesters, along with several non-Shiite participants, caucused and drafted a letter to Allawi and his cabinet that called for a dialogue with Sadr and "an immediate cease-fire and cessation of all military activities in Najaf and other Iraqi cities."

A four-person delegation from the conference then met with Allawi. When the meeting was over, the government announced that its plans to use force to expel Sadr from the shrine were on hold. In a reversal from its position a day earlier, Allawi's cabinet issued a statement pledging to refrain from military action against Sadr's militiamen and to keep an "open door" to a negotiated settlement.

On Monday, the conference took the next step, sending a delegation to Sadr insisting that he transform his militia into a political organization and vacate the shrine. The conference authorized the delegation to invite Sadr to join the political process and to give him safe passage out of Najaf to do so.

Hussein Mohammed Hadi Sadr, a Shiite cleric and a distant relative of Moqtada Sadr, read to the conference a communique prepared for delivery to the rebellious cleric.

Calling mediation a "holy mission," the communique urged Sadr to "respond to the urgent national request to change the Mahdi Army into a legitimate political entity . . . and to give the holy shrine of Najaf to the Iraqi people with the assurance of non-judicial pursuit of all those who withdraw from there."

No "advanced country should allow armed militias to be roaming in it," Hussein Mohammed Hadi Sadr told the conference, stating the "principles" behind the mission. He was interrupted eight times by applause and received a standing ovation at the conclusion.

While the conference as a whole appeared hopeful Monday, there were plenty of doubters as well.

Sameer Shaker Sumaidaie, a Sunni Muslim who was a member of the disbanded U.S.-appointed Governing Council, noted that Moqtada Sadr has reneged on previous agreements and might do so again. "Ultimately," said Sumaidie, "if he refuses to disarm his militia, it will have to be disarmed forcefully."

The conference's communique, he said, "gives him that clear choice. He has to say yes or no. If he does not say yes and he says no, then the government to a large extent will be absolved" if it has to use force.

The conference, though an exercise in democracy, has been accompanied by violence. A half-dozen mortar rounds landed near the heavily fortified conference center Sunday, killing two people and wounding 17 others at a nearby transportation depot, where three buses were reduced to charred hulks. The meeting was not interrupted, but the attack pierced an extraordinary security umbrella that involved curfews in nearby neighborhoods and numerous vehicle checkpoints.

The Shiite protest over Najaf Sunday provided a window into the chaotic fervor with which Iraqis are embracing democracy. Through their demands of Allawi, the delegates started to create a balance of power in the political system, even before winnowing themselves into a 100-member national assembly. But the protest also revealed the degree of Sadr's influence and the extent to which Iraqi society remains riven by differences that could impede its democratic transition.

Speaker after speaker rose Sunday to condemn the use of force against Sadr and his militiamen. "What is happening in Najaf is much more important than this conference and demands our immediate attention," one man intoned. Another likened the tactics used by U.S. and Iraqi security forces to those employed by the military under Saddam Hussein's government to crush Shiite dissent. A woman rose to criticize Sadr, saying, "It is not American cannons" that are responsible for the bloodshed there, but was shouted down.

Members of the interim government have maintained that few Iraqis endorse Sadr's lawlessness and that many back Allawi's tough tactics to restore order in this strife-torn country. But the delegates, who are supposed to represent Iraq's 25 million people, took a more nuanced approach to the standoff in Najaf, where scores of fighters from Sadr's Mahdi Army militia have been holed up in the Imam Ali shrine. Despite strong support for aggressive action to combat criminals and insurgents, many of the conference participants -- not just Shiites, but rival Sunnis as well -- rejected the idea of using force to liberate the shrine and apprehend Sadr.

"How can we have a conference if we have a war in Najaf?" growled Nadim Jabbari, the leader of a small Shiite party in Baghdad. "We must solve that problem first," he said Sunday.

Solving that problem delayed other business at the conference. The delegates are supposed to select the interim national assembly by Tuesday. By the end of the day Sunday, they had not even agreed on the rules by which members would be elected. The organizers want delegates to vote on slates of 81 candidates -- 19 members of the former U.S.-appointed Governing Council have been guaranteed seats -- but some participants, particularly those who are political independents, say they believe that method favors political parties and instead want assembly members to be elected individually.

The assembly, which will have the authority to veto decisions issued by Allawi's cabinet, will be replaced after national elections are held. Those elections are scheduled for January.

The conference had been postponed for two weeks to attract more participants. It was supposed to be limited to 1,000 members, but political advisers from the United Nations asked organizers to invite 300 additional people, many of them from religious and ethnic groups that were deemed underrepresented. More than 1,100 of the 1,300 attended on Sunday, said Fouad Masoum, the conference chairman.

"Your blessed gathering here is a challenge to the forces of evil and tyranny that want to destroy this country," Allawi told participants in an opening address. He called the gathering a "first step that will open up horizons of dialogue" and serve as "an example for democracy and freedom" in the Middle East.

But it was Allawi's vow last week that he would not negotiate with Sadr that resonated even more profoundly at the conference. Abdul-Latif, the minister of state for provincial affairs, said that the government had repeatedly asked Sadr to withdraw his militia from the shrine. Abdul-Latif also noted that Allawi's national security adviser recently traveled to Najaf to negotiate, but Sadr would not meet with him.

Abdul-Latif said the government would give Sadr "reasonable time" but not an indefinite period. If the militiamen do not vacate soon, he said, "we will pursue them."

In his opening address, President Ghazi Yawar urged the delegates to "achieve national consensus and agreement."

Ashraf Jehangir Qazi, a former Pakistani ambassador to Washington who is serving as U.N. Secretary General Kofi Annan's special representative in Iraq, told delegates that the gathering was "a critical milestone on the path toward a goal shared by all Iraqis -- the goal of seeing their beloved country become a stable, pluralistic and inclusive democracy." He insisted that strife could not be addressed "through security measures alone. They require political consensus-building, rehabilitation measures and the promotion of the rule of law."

Barbash reported from Washington.