BAGHDAD - The Iraqi government's Parliament base fragmented yesterday with the defection of a hard-line Shi'ite bloc.
The followers of radical Shi'ite cleric Moqtada al-Sadr announced that they were withdrawing from the Shi'ite alliance in Parliament, where they hold 30 of the 275 seats.
Separately yesterday, an Al Qaeda front group threatened to assassinate Sunni leaders who "stained the reputations" of their people by supporting Americans.
The two developments cast doubt over prospects for political and military progress in Iraq as the US Senate gears up for a debate this week on Democratic demands for deeper and faster troop cuts than President Bush plans.
The threat against Sunni leaders came from the Islamic State of Iraq, which claimed responsibility for the assassination Thursday of Abdul-Sattar Abu Risha, the organizer of the Sunni Arab revolt against Al Qaeda in Anbar Province. Bush met Abu Risha at a US base in Anbar this month and praised his courage.
In an Internet posting, the Islamic State said it had formed "special security committees" to track down and "assassinate the tribal figures, the traitors, who stained the reputations of the real tribes by submitting to the soldiers of the Crusade" and the Shi'ite-led government of Prime Minister Nouri al-Maliki.
"We will publish lists of names of the tribal figures to scandalize them in front of our blessed tribes," the statement added.
In a second statement, the purported head of the Islamic State, Abu Omar al-Baghdadi, said he was "honored to announce" a new Ramadan offensive in memory of Abu Musab al-Zarqawi, the founder of Al Qaeda in Iraq who was killed last year in a US air strike.
Hours after the announcement, a car bomb exploded late yesterday in a mostly Shi'ite area of southwest Baghdad, killing at least 11 people lined up to buy bread at a bakery.
Two of the dead were children, police said.
The blast occurred at the start of iftar, the evening meal at which Muslims break their dawn-to-dusk Ramadan fast. The bloodshed was a blow to government hopes that a peaceful Ramadan would demonstrate the success of the seven-month increased troop presence in the capital.
Also yesterday, the US military said a soldier from the Army's Task Force Marne was killed and four were wounded the day before when a bomb exploded near their foot patrol.
The Sunni revolt that Abu Risha spearheaded has led to a dramatic improvement in security in Anbar, although the province remains unstable. Nevertheless, the decline in violence in Ramadi and other Anbar cities has been one of the major success stories for the US mission in Iraq.
A prominent Sunni sheik said the province's leaders would not be intimidated by Al Qaeda threats and would continue efforts to drive the terrorist movement from their communities.
"We as tribesmen will act against the Al Qaeda, and those standing behind it who do not want us to put an end to it," Ali Hatem al-Suleiman said.
The Qaeda threats and the assassination of Abu Risha, one of the best-protected tribal figures in Iraq, could cause some tribal leaders in other Sunni provinces to reconsider plans to stand up against the terror movement.
With US and Iraqi overtures to the Sunnis under threat, the government faced a deepening political crisis with the announcement that Sadr's followers were pulling out of the Shi'ite alliance.
The announcement, made to reporters in Najaf, means the Shi'ite-led government can count on the support of only 108 Parliament members - 30 short of a majority. However, it could probably win the backing of the 30 independent Shi'ite parliamentarians, as well as some minor parties.
The decision by Sadr's followers may complicate further US-backed efforts to win parliamentary approval of power-sharing legislation, including the oil bill and an easing of curbs that prevent former Saddam Hussein supporters from holding government jobs.