Rebellious cleric Moqtada Sadr on Tuesday rebuffed a delegation of Iraqi political leaders seeking a face-to-face meeting to persuade him to disband his militia and vacate a large Shiite Muslim shrine here, increasing chances of intensified U.S. and Iraqi military action to evict him and his followers.

The eight-member delegation, led by a senior cleric who is a relative of Sadr's, crossed a U.S. military cordon and braved nearby gun battles to reach the gold-domed Imam Ali shrine, one of Shiite Islam's holiest sites. The goal was to forge a deal with Sadr to end a potentially destabilizing confrontation and convert his militia into a political organization that would take part in elections.

The delegates, who waited for Sadr for three hours in a darkened receiving room, never saw him. His aides said he failed to appear because of continued aggression by U.S. forces, which have engaged in intense offensive operations against Sadr's militiamen in Najaf's old city, near the shrine. Qais Qazali, a Sadr spokesman, condemned the United States for "preventing peaceful negotiations."

Military assaults occurred before and after the delegation's visit, with U.S. Army units using Bradley Fighting Vehicles to expand their zone of control in the old city and U.S. Marines lobbing 155mm artillery shells into the massive cemetery north of the shrine. But a senior American commander in Najaf insisted that operations paused during the attempted peace talks. "We sat still for the entire time," said Maj. David Holahan of the 11th Marine Expeditionary Unit, which commands U.S. forces in Najaf.

To this correspondent, who accompanied the delegation, it appeared that both sides were partly correct. As the delegation arrived, the distinct, repetitive thud of a Bradley's 25mm main cannon echoed through the labyrinthine alleys leading to the shrine, answered occasionally by the explosion of a rocket-propelled grenade, likely fired by Sadr's Mahdi Army militiamen. But as the evening wore on, the sound of American armaments ceased and was replaced with more than a dozen bone-rattling booms of Mahdi Army mortars being fired from next to the shrine.

As the delegation approached the shrine in two sedans, without armed guards and with only white undershirts tied to the antennas to indicate they were noncombatants, members saw a city in the vise of war.

In neighborhoods away from the shrine that are under U.S. control, the streets were deserted save for patrols by Iraqi policemen wearing face-covering balaclavas.

In closer-in areas, militiamen roamed the streets with assault rifles and rocket-propelled grenade launchers. They had set up barricades on streets and gun nests in abandoned buildings. To avoid detection by Marine snipers perched atop the city's tallest buildings, reinforcements were being ferried in through a network of alleys that cut through rows of old brick buildings.

Although the Mahdi Army has been described by some U.S. military officials as a hobbled outfit that has taken hundreds of casualties in the past week, Sadr's militia appeared to be everywhere in the neighborhood near the shrine. Scores of armed young men walked along the streets.

When the delegation entered the walled-off, white marble courtyard of the shrine, about 1,000 of Sadr's supporters converged on the group, stamping their feet, raising their fists into the air and shouting, "Long live Moqtada!"

To Sadr's followers, the United States' June 28 transfer of political authority to an interim Iraqi government was meaningless. In their view, the presence of 140,000 U.S. troops on Iraqi soil means their nation is still under occupation.

"We want peace. We don't want war," declared Samir Narem, a tall, bearded man in an ankle-length tunic who joined the crowd that turned out for the delegation. "But we don't want occupation. We will die before we give up."

As dusk turned to darkness and a warm breeze wafted through the city, strings of green lights hanging from the wall of the shrine illuminated the courtyard and the intricate mosaics on the brick walls. Scores of young men, who had completed their evening prayers, reclined on large carpets unrolled over the marble floor. Every now and then, someone would lead the crowd in chants of "Moqtada! Moqtada! Moqtada!"

"We are here to protect the shrine from the Americans and their pawns in the government of Allawi," said an English-speaking engineer from the southern city of Basra, referring to interim Prime Minister Ayad Allawi. "If we have to give our lives to protect this place, so be it. We will go to paradise," said the man, who gave his name only as Abbas.

The members of the delegation are all participants in a national conference that was convened Sunday in Baghdad to select an interim national assembly. Although the assembly was to have been elected by Tuesday, the proceedings have been dominated by efforts to resolve the crisis in Najaf, where U.S. forces have been in combat with the Mahdi Army for weeks. The conference is scheduled to reconvene on Wednesday to hear from the delegation and to choose members of the new assembly.

Political leaders spent much of Tuesday in closed-door meetings trying to persuade leaders of Shiite religious parties to back down from a demand that their members receive at least 51 of the 100 seats. Although Shiites constitute a majority of Iraqis, conference organizers and leaders of parties representing Sunni Muslims and ethnic Kurds do not want all the Shiite members to be chosen by religious parties.

The delegation to Najaf was led by Hussein Mohammed Hadi Sadr, an elderly Shiite cleric and distant relative of Moqtada Sadr. It also included a woman who is a cousin of Moqtada Sadr; a leader of a Shiite religious party; a member of the former U.S.-appointed Governing Council; and the brother-in-law of interim President Ghazi Yawar.

The group had wanted to travel to Najaf on Monday but was unable to arrange transportation.

Concerned that its convoy might be ambushed along the way, the group was flown to a Marine base on the outskirts of Najaf by a U.S. Army Black Hawk helicopter. Once delegation members arrived at the base, they had to wait an hour for unmarked civilian vehicles to take them into the city.

As soon as they entered the shrine, they got signals that they would not meet with Sadr. "If you have connections with the U.S. leader, you should call him and ask him to withdraw his forces a little bit so that we can bring Sayed Moqtada Sadr safely here," said Ali Smeisim, Sadr's deputy, using a religious honorific for the cleric.

"Isn't he in Najaf?" Hussein Sadr asked.

"He is -- in a secret, secure place," Smeisim said.

"The U.S. forces do not follow our orders," Hussein Sadr said. "It is not necessary for him to come. Take me to him."

"Well, it's a secret place," Smeisim responded. "As you know, we are in war conditions."

With that, the delegation was left to wait for three hours before leaving. The group gave Smeisim a communique from the national conference that calls for Sadr to dissolve the Mahdi Army, vacate the shrine and join the political process.

As the delegation members left, they publicly expressed optimism. Sadr's representatives "don't reject what came from the national conference," Hussein Sadr told reporters. "The message reached Moqtada Sadr."

As he spoke, his voice was quickly drowned out by a loud fusillade of gunfire and the emotional outburst of militiamen as a corpse shrouded in white, signifying that the deceased was a martyr, was paraded through the courtyard.

Rajaa Khozai, one of the delegates, said she hoped the group would be able to return Wednesday or Thursday and meet with Sadr. But there were no immediate plans to do so.

One of the members, speaking on condition of anonymity, said the meeting "was not as successful" as they had hoped. "Moqtada needs to make a dramatic move for peace," the member said. "We had hoped to convey that to him directly."

As they prepared to board their helicopter to take them back to Baghdad, the members seemed resigned to a continuation of the fighting and perhaps an escalation.

"At least we showed Moqtada Sadr good faith," said Akeel Saffar, a member of Allawi's Iraqi National Accord party. "Now let's see what Moqtada does."

Correspondent Karl Vick and special correspondent Omar Fekeiki in Najaf contributed to this report.