But the level of violence has increased so much since the Feb. 22 bombing of a Shiite shrine in Samarra that some U.S. officials and experts question whether the Iraqis are capable of handling the situation without U.S. help.

Earlier this week, police intervened to stop clashes between a Shiite and a Sunni tribe south of Baghdad, according to officials who spoke on condition of anonymity for fear of reprisal.

Casualty figures were unclear, but funerals for 12 Shiite militiamen killed in the clashes were held Thursday in Kut, 100 miles southeast of Baghdad, residents said.

Iraqi forces designed to cope with Sunni Arab insurgents now face the threat of sectarian violence from militias and death squads ¡ª some of them believed to be within the ranks of the police and army.

Iraqi politicians have been unable to agree on who will head the Defense Ministry, which runs the army, and the Interior Ministry, which directs the police. Sunni Arab and Shiite political leaders expressed hope that compromise candidates would be found to head the two ministries by Saturday.

A firm hand guiding the two ministries could lay the groundwork for shifting security responsibilities from U.S.-led forces to the Iraqi army and police. U.S. officials have conceded that could take longer than Iraqi officials wish.

Iraq's armed forces and police number about 254,000 and should reach about 273,000 by year's end. That, according to al-Maliki, is when "responsibility for much of Iraq's territorial security should have been transferred to Iraqi control" ¡ª except for Anbar province and Baghdad, two of the most violent areas.

Al-Maliki and Blair said Monday that Iraqi security forces would start assuming full responsibility for some provinces and cities next month. They declined to set a date for a coalition withdrawal.

The Iraqi army needs to recruit at least 5,000 troops in Anbar, the western province that U.S. Ambassador Zalmay Khalilzad acknowledged is not fully under coalition or Iraqi government control.

"I believe that parts of Anbar are under the control of terrorists and insurgents. But as far as the country as a whole is concerned, it is the coalition forces, along with Iraqi forces, who are in control," Khalilzad told CNN.

The U.S. Army has said it wants make up the shortfall in Anbar with locally recruited troops, but such a move probably will not be possible unless the Defense Ministry is controlled by a Sunni Arab.

"Negotiations are under way in order to reach a decision regarding the appointment of the ministers of defense and interior. Within the coming two days, the decision will be made," Adnan al-Dulaimi, head of the main Sunni Arab party, the Iraqi Accordance Front, told The Associated Press.

Sunni Arabs also have sought the ministry as a counterbalance to the Shiite-run Interior Ministry, which many members of the minority blame for failing to disband militias they say are responsible for sectarian death squads.

Al-Dulaimi said his coalition presented six Defense Ministry nominees for vetting and made it clear that Sunni Arabs want an interior minister "who is not linked to militias."

Shiite deputies said a seven-member selection committee would keep meeting daily and hoped to make a choice by Saturday, the day before parliament convenes. The 275-member body will have to approve any candidates.

A U.S. Army soldier died Tuesday when his patrol was attacked by small arms fire and rocket-propelled grenades during an operation to clear roadside bombs south of Balad, 50 miles north of Baghdad, the military said.