NAJAF, Iraq -- Renewed fighting between Shi'ite militants and US and Iraqi forces appeared likely here after talks between rebel cleric Moqtada al-Sadr and the Iraqi government collapsed yesterday, raising fears of a climactic showdown in one of Shi'ite Islam's holiest cities.
Mowafak Rubaee, national security adviser to interim Prime Minister Ayad Allawi, said that negotiations for a resolution had broken down and that a cease-fire, declared Friday, no longer applied.
"It is with deep sorrow and regret that I announce the failure of efforts to end the crisis in Iraq peacefully," Rubaee said. "Military clearing operations" would resume "to establish law and order in this holy city," he added.
Among the Shi'ite negotiators, there were assertions of bad faith in the official Iraqi leadership. "It is a conspiracy to commit a big massacre," Sadr's top negotiator, Sheik Ali Smeisim, told the pan-Arab Al-Jazeera television station.
It was unclear, however, when US troops and members of the Iraqi National Guard and police would relaunch the offensive against Sadr's followers, which began Thursday. Before the truce took effect, US and Iraqi forces had encircled the sacred Imam Ali mosque in Najaf's Old City, where Sadr and as many as 1,000 members of his Mahdi militia are believed to be sheltered.
A few hours after talks fell apart, US forces began mobilizing to resume the intense combat that has raged in Najaf since Aug. 5. Hundreds of troops lined up in tanks and other armored vehicles at a base on the northern edge of the city.
But as the convoy was ready to roll, officers ordered that the engines be cut and the troops be returned.
"Allawi has decided there has to be an Iraqi solution to the problem," said Major David Holahan, executive officer of the First Battalion, Fourth Marine Regiment. "We were ready to help them if they directed us to. . . . We developed a plan in case one was requested, but we were not directed to execute the plan."
Still, one of Sadr's aides warned earlier that "a massacre" was just hours away, and tense anticipation saturated the night air.
The failure to reach an agreement casts a pall over a three-day conference due to begin today in Baghdad to help choose a 100-member national assembly with limited powers. The government touts the conference as a key step on the road to democratic elections in January, but some groups, including Sadr's militants, are boycotting the gathering, which they label a US creation.
Each side blamed the other for the failure of the Najaf talks, which had offered a slight hope for a negotiated end to a confrontation that has left hundreds dead here and in other Iraqi cities where Sadr supporters have risen up in solidarity.
There were conflicting accounts, even within the Sadr camp, as to what caused the dialogue to halt so abruptly. A Sadr spokesman, Qais Khazali, said the cleric had agreed to almost all the government's demands before Rubaee, Allawi's chief negotiator, suddenly pulled out of the talks. Khazali accused the government of never intending to negotiate in good faith.
Rubaee said dialogue foundered after Sadr refused to meet with him face to face, despite repeated promises.
As the prospect of renewed combat arose, attention refocused on Najaf's ancient Imam Ali mosque, which the militants have used as a launching pad for attacks and a shield against return fire. Iraqi and US officials have refrained from any offensive against the shrine for fear of damaging it and igniting the anger of Shi'ites worldwide, who revere it as the burial place of the prophet Muhammad's son-in-law.
US planners say their strategy is to isolate Sadr's forces inside the mosque. Any move to rout Sadr from the shrine would be conducted by Iraqi forces -- under the supervision of the US military -- to lessen political fallout.
Allawi has expressed his determination to stamp out the rebellion by Sadr and his followers, who have challenged his fledgling government's legitimacy and cast themselves -- with increasing success -- as the true defenders of Iraq's sovereignty from US control. Allawi has staked his reputation on proving himself a leader capable of restoring order.
But Sadrhas kept the government off-balance by mixing appeals for peace talks with calls to his followers to keep on fighting.
Material from the Associated Press was included in this report.