BAGHDAD -- Clashes persisted for a second day yesterday in a Sunni district of Baghdad between Iraqi forces and what appeared to be local militiamen who feared that Shi'ite death squads had infiltrated the community.
US and Iraqi troops sealed off streets to the Azamiyah district, and residents reported the area appeared quiet after clerics broadcast appeals for calm over loudspeakers from the main Sunni mosque. At least 13 people died in the two days of fighting, Iraqi officials said.
There were conflicting reports about what triggered the clashes, which underscored the rising tensions between Shi'ite and Sunni Muslim communities that threaten to plunge Iraq into civil war.
The US military said trouble began before dawn Monday when gunmen fired on an Iraqi Army patrol. Fighting escalated four hours later when 50 gunmen assaulted a US-Iraqi police checkpoint, prompting US and Iraqi reinforcements to rush to the scene, a US statement said.
Although the clashes ended Monday afternoon, they broke out again before dawn yesterday when rumors swept Azamiyah that paramilitary commandos from the Shi'ite-led Interior Ministry had entered the area.
Many Sunnis consider Interior Ministry commandos, many of them veterans of the Shi'ite Badr Brigade militia, as little more than sectarian death squads responsible for kidnapping and killing hundreds, possibly thousands, of Sunni civilians during the past year.
''Just after 6 a.m., the mosques began calling 'Allahu Akbar' [God is great] over and over, which is the signal that there's trouble, that the neighborhood is under attack," one resident, Riyadh Zoheir, said by telephone from Azamiyah.
As the alarm sounded, masked gunmen took up positions on rooftops, firing at military vehicles. Gangs of armed men roamed from house to house, urging Sunni families to provide male members to help defend the neighborhood, residents said.
Defenders included members of a neighborhood watch group formed after the Feb. 22 bombing of a Shi'ite shrine in Samarra. The bombing triggered reprisal attacks against Sunni mosques and clerics, raising the specter of all-out sectarian war.
Several of the dead were members of the watch force, residents said.
''They came in wearing police clothes, but they weren't police," a watch group member said, speaking on condition of anonymity for fear of reprisal. ''We defended our neighborhood, our mosques, and our honor."
Rumors spread that some of the outsiders included armed men ''who did not speak Arabic well -- meaning they were Iranians or Iranian-Iraqis," Zoheir said, referring to young Shi'ites who grew up in Iran and returned after Saddam Hussein's fall.
Iraqi officials moved quickly to contain the violence. Local police commanders issued statements assuring Azamiyah residents of their safety. A leading Sunni cleric, Abdul-Salam al-Kubaisi, broadcast an appeal over a mosque loudspeaker, urging Sunnis to ''resume normal lives."
Iraqi Army units patrolled the streets. Sunni Arabs tend to favor the army, which is controlled by the Sunni defense minister, over forces of the Shi'ite-led Interior Ministry.
''For the past days, the situation was miserable," said Ziyad Younis, a university lecturer.
Sunni anger has welled at a time of political instability as Iraq's ethnic and religious factions struggle to form a government of national unity. Talks have been stalled for months over the issue of who should be the next prime minister, with the Sunnis and Kurds steadfastly rejecting the Shi'ite nomination of incumbent Ibrahim al-Jaafari.
Jaafari has refused to give up the nomination that he narrowly won in a Shi'ite caucus. Shi'ite leaders met yesterday to discuss the possibility of a new Shi'ite candidate, but prospects for a quick end to the stalemate were in doubt as Jaafari's Dawa party pledged to support him for a second term.
In other developments:
Seven people were killed when a bomb exploded outside a cafe in eastern Baghdad, police reported.
A policeman was shot dead near his home in Basra, officials said.
Two bodies, both shot in the head, were found in southwestern Baghdad.