It was at least the second formal overture al-Sadr has made to Abdul-Aziz al-Hakim and his Supreme Islamic Iraqi Council, the largest Shiite political party, in less than a week.
Peace between the two - who each control powerful militias - is seen as key to preventing the outbreak of widespread fighting in oil-rich southern Iraq, where the British military recently handed over responsibility for security to Iraq's government in Basra, the last province it controlled.
The U.S. military, meanwhile, announced the death of three of its soldiers late Thursday.
It said two were killed and a third wounded in a small arms attack Thursday in Diyala province northeast of Baghdad.
A soldier was killed the previous day in south Baghdad when his dismounted patrol hit a roadside bomb, the military said. The Wednesday fatality is the first U.S. military death to be reported in 2008, taking to at least 3,907 the number of members of the U.S. military who have died since the Iraq war began in March 2003, according to an Associated Press count.
A delegation from al-Sadr's office in Kufa, led by sheik Muhanned al-Gharrawi, met with the Dhi Qar provincial governor Aziz Kadhim Alwan, a member of al-Hakim's party, and other local officials in Nasiriyah, about 320 kilometers (200 miles) southeast of Baghdad. In the past, al-Sadr followers have had violent clashes with the governor's guards.
"The province should live in peace and security without armed violence and disorder," Alwan said after the meeting. Al-Gharrawi said the talks were meant to "end political and military" violence in the province and "to protect citizens' lives."
In August, followers of al-Sadr and fighters loyal to al-Hakim clashed in the holy city of Karbala during a religious festival, killing 52 people. In October, the two leaders signed their truce, which has largely held.
On Saturday, al-Sadr called for reconciliation between his followers and Iraqi security forces in Karbala, where authorities have cracked down on his followers since the August violence. "This initiative comes as a response to the events that took place in Karbala, when more than 50 pilgrims died," al-Gharrawi said then.
Shortly after the Karbala fighting, al-Sadr announced he was freezing the activities of his Mahdi Army militia for six months - a move that both Iraqi and American officials say has been a major factor in the sharp decrease in violence Iraq has seen in the last six months.
The differences between the two camps, however, are too complex and deep to be resolved at the level of Thursday's meeting. Their rivalry mirrors class distinctions within the Shiite community as well as the longtime competition of the al-Sadr and al-Hakim families for the religious leadership of the holy city of Najaf, Shiite Islam's primary seat of learning.
The rivalry is likely to come to a head when local elections are held nationwide, possibly this year, when the two camps will spare no effort to dominate provincial councils in nine provinces south of Baghdad. Beside the oil reserves, southern Iraq has a prize in the wealth and prestige of the shrine cities of Najaf and Karbala, visited by millions every year.
Separately on Thursday, al-Hakim called for unity among Shiites, arguing that closing ranks would benefit the whole of Iraq since they are the majority.
"Every one must work to support and boost this unity," he told supporters in Najaf.
He also acknowledged the contribution of U.S.-backed, anti-al Qaeda in Iraq Sunni groups to the decline in violence and called for their use in the continuing fight against al Qaeda.
"Today, we are witnessing the decline of terrorism and the progress of reconciliation on the popular level with Sunni-Shiite solidarity," he said, alluding to the government's perceived failure to achieve political reconciliation between Sunni, Shiite and Kurdish groups.
The Sunni militias, more than 70,000-strong, have been credited by American commanders as being instrumental in what they say is a nearly 60-percent reduction in violence in the last six months, which was also effected by the dispatch of an additional 30,000 U.S. troops that began in June.
But Prime Minister Nouri al-Maliki's government has been deeply uneasy about the potential for the Sunni fighters - now better organized and armed - to switch sides again, posing a threat to stability and the Shiite domination that followed the ouster of Saddam Hussein's Sunni-led regime.
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