Disguises Used in Attack on Troops

In December 2004, a U.S. base in Mosul was penetrated by a suicide bomber who killed 22 people, including 14 U.S. service members. But Saturday's attack appeared to present a new danger to authorities in Iraq: assailants who disguise themselves as officials and travel in convoys.

"The way it happened and the new style, the province has not seen before," said Abdul al-Yasri, head of the provincial council in Karbala. "And this will make us insist on carrying on the security procedures even on official delegates and diplomats when they are coming to Karbala province."

Military officials said Sunday that the cause of the helicopter crash, which killed 12 soldiers northeast of Baghdad on Saturday, also remained under investigation. They said they could not confirm accounts by Iraqi officials and civilians who said it was shot down by insurgents in a Sunni Muslim-dominated area of Diyala province. U.S. officials initially reported that 13 soldiers died in the crash.

The military also announced that two Marines were killed in separate combat incidents Sunday in Anbar province in western Iraq. The military said four soldiers and one Marine were killed in combat Saturday in Anbar. The service members' names were withheld pending notification of their relatives, officials said.

The British military said that a roadside bomb in the southern city of Basra killed one British soldier and wounded four, the Reuters news agency reported.

Reports of carnage targeting Iraqis also continued Sunday. A passenger stepped off of a public minivan in central Baghdad, leaving behind a bomb that exploded, killing four police officers and three civilians, said Gen. Sadoun Qasim of the Iraqi Interior Ministry.

Elsewhere in Baghdad, at least five people were killed by two improvised explosive devices.

Four Iraqis, including a 1-year-old and a 5-year-old, were killed Friday by an improvised explosive device in the city of Yusufiyah, south of Baghdad, the U.S. military said in a statement. An ambulance transporting one of the wounded struck another roadside bomb en route to the hospital. The second blast caused no injuries.

In Ramadi, 60 miles west of Baghdad, a hospital official said the body of a fighter from the insurgent group al-Qaeda in Iraq was taken to the hospital after being discovered in a house. The 31-year-old man had been carrying a fake Iraqi passport and a real Saudi one, according to Muhammad Ismail, a doctor at the hospital.

Sadr Bloc Ends Boycott Of Iraqi National Assembly

The parliamentary bloc of radical Shiite cleric Moqtada al-Sadr announced an end to a boycott that has kept Iraq's young National Assembly semi-paralyzed for two months.

The Sadr bloc returned to the assembly after a parliamentary committee and the speaker, Mahmoud al-Mashhadani, agreed to a series of demands, said Falah Hasan Shenshel, a member of the Sadr bloc.

The demands included establishing a timetable for the buildup of Iraqi troops and the withdrawal of U.S. troops, and a condition that the presence of foreign troops would not be extended without a vote by the assembly, Shenshel said. U.S. troops should retreat from Iraqi cities and return to their bases by the end of August, he said.

"By doing so, America would confirm that it came to Iraq as a liberator and not as an occupier," Shenshel said.

Sadr's movement has 30 seats in the 275-member parliament, and his political loyalists have called for a prompt withdrawal of U.S. troops. He is widely regarded as a focal instigator of the sectarian violence that has ravaged the country in recent months.

Also Sunday, two officials said that Prime Minister Nouri al-Maliki had ended his protection of Sadr's militia, the Mahdi Army, after U.S. intelligence convinced him that the group was infiltrated by death squads, the Associated Press reported. The officials spoke on condition of anonymity because the information was confidential.

"Al-Maliki realized he couldn't keep defending the Mahdi Army because of the information and evidence that the armed group was taking part in the killings, displacing people and violating the state's sovereignty," one official said.

Correspondent Joshua Partlow and special correspondents Waleed Saffar, Naseer Nouri and Saad Sarhan contributed to this report.