BAGHDAD, Iraq — As fighting between U.S. forces and Shiite militiamen flared again on Monday in the southern city of Najaf, a conference of Iraqis gathering here to form a national assembly decided to send a delegation to the city.

As many as 60 political, religious and social leaders will leave Tuesday morning for Najaf, where fighters loyal to the cleric Muqtada al-Sadr and based in Shiite Islam's holiest shrine have been battling U.S. and Iraqi forces. Delegates said the group would ask that al-Sadr disarm his militia, leave the shrine and join the political process.

One of the Iraqi delegates, Aziz al-Yasseri, said that aides to al-Sadr had agreed to meet the group. It was not clear whether al-Sadr would personally attend or send aides, as he did with government envoys late last week.

Even as delegates worked to find vehicles and private security guards for the highly dangerous road south, fighting resumed between Muqtada al-Sadr's militia, the Mahdi Army, and U.S. forces.

One Army battalion skirmished with insurgents in the huge cemetery that has been the scene of the heaviest fighting, just north of Najaf's old city, while another attacked several buildings around the outer edge of the old city, where insurgents were believed to be hiding. At nightfall, Marines set out to raid more buildings in the district.

Near the southern city of Amara, Mahdi Army fighters struck at the heart of Iraq's economic engine on Monday, setting fire to an oil field, a spokesman for Allawi said.

Fighting also broke out in Baghdad, in the Shiite district of Sadr City, another of Muqtada al-Sadr's strongholds. Rebel fighters detonated a bomb under an American tank and then set it afire, Reuters reported. The crew escaped with minor injuries.

Al-Sadr has previously refused requests to disarm and leave the shrine. But those demands were set by Allawi's government, which al-Sadr has called illegitimate, and the hope was that al-Sadr would be more receptive to the conference delegates, who represent an ethnic, religious and social cross section of Iraq's 25 million citizens.

"Now he's in a good position to accept these suggestions," said Ahmad Barak, a former member of the now defunct Governing Council, set up by the Americans to help run the country after the war. "The solution is being offered not by the government but by the conference. It's a big difference."

The Iraqi government has said Iraqi troops will conduct any future battles with al-Sadr's militia, although whether Iraqi forces are capable of defeating the guerrillas without American aid is unclear.