As delicate negotiations with aides of outlaw Shiite cleric Moqtada al-Sadr falter, Shiite tribal and religious leaders are beginning to worry that the month-long standoff between Mr. Sadr's Mahdi army and US forces might expand into an intra-Shiite conflict that could threaten Iraq's stability.
In recent days, Shiite political groups have been ratcheting up their rhetoric against Sadr - especially in Najaf, where leading Shiite clerics are rapidly losing patience with his presence.
On Tuesday, Sheikh Sadr al-Din al-Qubanchi, a senior cleric aligned with Iraq's largest Shiite political group, the Supreme Council for the Islamic Revolution in Iraq (SCIRI), called for mass demonstrations in Najaf against Sadr.
"We all want to protect the holy places against danger and prevent any possibility that the city will be turned into a military bunker or [have] street fighting," says Mr. Qubanchi. "And we have to cooperate to achieve this."
If that doesn't work, Qubanchi hinted that SCIRI would use its 10,000-strong militia, the Badr Brigade, to push Sadr's militia to the outskirts of town, where US troops could easily finish them off.
"We could have a bloody confrontation between Shiite groups in Najaf," says Sheikh Fatih Kashif al-Ghitta, a cleric from a prominent Najaf family. "That would be a very dangerous escalation - it could cause deep divisions in the Shiite community."
Tensions have risen between Sadr and more moderate Shiite clerics in recent weeks, with some Sadr aides openly criticizing Shiite clerics.
"Where are the ones who said that Najaf was a red line?" demanded Sadr aide Sheikh Abdul-Hadi al-Darraji, in a thinly veiled reference to Shiite Grand Ayatollah Ali al-Sistani, who called Najaf's city limits a "red line" that American troops should not cross.
"We came here to prove that the evil forces won't be able to destroy Islamic unity," says Mr. Darraji, speaking to thousands of mostly Shiite worshipers at a joint Sunni-Shiite prayer surface at Baghdad's Sunni Abu Hanifa mosque last Friday.
"Your enemies came to plant a rift between the Shiites and the Sunnis, and they failed because Islam is one. And after the occupiers finished from Fallujah they turned toward Najaf to attack our leaders and our symbols."
Thursday, gunfire and explosions rocked the city of Karbala, 50 miles south of Baghdad, with fighting concentrated near the holy Imam Abbas shrine. It was the third straight day of clashes in Najaf and Karbala, Shiite Islam's two holiest cities, where Sadr's Mahdi army has been skirmishing with US troops for more than a month. Sadr himself remains in Najaf, where he has been holed up since early April.
Meanwhile, Mr. Ghitta and other moderate Shiite leaders scrambled to salvage an agreement with senior Sadr aides to disarm his Mahdi army. First presented a month ago, the deal offered Sadr a way to save face by surrendering himself to Iraqi tribal authorities, rather than American forces, to stand trial for the assassination of a rival Shiite cleric.
In exchange, the Mahdi army would disband and both it and American forces would pull out of Najaf. Last week, the deal's architects gave Sadr a deadline of May 15 - Saturday - to accept the deal.
As the deadline looms, Sadr continues to stall. On Tuesday, speaking at a rare press conference, he urged his supporters to continue fighting and invoked the Vietnam War. But he also said he would be willing to disband his militia if Ayatollah Sistani, Iraq's top Shiite cleric, issued a fatwa, or edict.
But some Shiite leaders fear that could deepen the divisions within Iraq's majority Shiite community.
"Moqtada's not very clear with us," says Sheikh Hussein Ali al-Shaalan, a Shiite tribal leader who is involved in the negotiations. "He wants Sayyid Sistani to be involved in dissolving the Mahdi army, but Sayyid Sistani doesn't want to be involved, because if he gives a fatwa and Moqtada doesn't follow it, this could cause big problems."
On Wednesday, Najaf's US-appointed governor, Adnan al-Zurufi, tried to break the stalemate by offering to let Sadr wait to hold up his end of the bargain until after June 30, when the US is due to hand over sovereignty to an interim Iraq government.
But almost immediately the possible delay began to cause problems.
"If there is a trial after June 30, it could cause security problems that would weaken the new government," says Ghitta. "This would create a dangerous situation. I doubt that the US would agree to this kind of delay."
Senior US officials agree, saying that two conditions are not negotiable: Sadr has to surrender and has to stand trial, before the June 30 handover of power.
"The offer from the Najaf governor was made without consultation with the coalition," says a senior coalition official. The official, who asked not to be named, called Sadr's offer "unacceptable."
And on Wednesday, US administrator Paul Bremer told Iraq's US-appointed Iraqi Governing Council that he would not accept any solution that let Sadr wait until after June 30 to go to trial. This caused some divisions within the council, with one member accusing Bremer of being "an extremist."
But while fellow Shiites grow increasingly frustrated with Sadr's delaying tactics, occupation officials suggest that drawing out the conflict could only hurt his cause, as he loses supporters day by day.
"They're searching in the wind for something," says the coalition official. "Some of the die-hard loyalists are still with him, but many others have left."
Other observers agree, saying that coalition forces are likely to win a war of attrition with Sadr, especially as he loses ground with other Shiites.
"The Americans have a two-part political strategy," says Ali Abdul-Ameer, editor of Baghdad, the daily newspaper of the pro-US Iraqi National Accord political party. "First, to isolate Moqtada from the Shiite clerical leadership and the major Shiite political parties; and second, to weaken the Mahdi army day by day. Moqtada is now contained."
But if that containment comes at the cost of Shiite unity, says Ghitta, it won't be worth the price. "Moqtada is just trying to delay things - he has been trying to delay all along," says Ghitta. "Moqtada's people don't understand the value of time. And we are running out of time."