Insurgents using roadside bombs and small arms fire killed three U.S. soldiers and wounded four, while five Iraqis died in other attacks, authorities said Thursday.

U.S. aircraft, meanwhile, destroyed more militant safe houses near the Syrian border, and apparently killed a senior Al Qaeda (search) in Iraq figure who was using religious courts to try Iraqis who supported coalition forces, the military said.

In Baghdad, back-room dealmaking continued as political blocs sought to forge new alliances before Friday's deadline for them to file candidate lists for the Dec. 15 parliamentary election. Key Shiite politicians said talks were still under way on a unified Shiite ticket and no final agreement had been reached.

On Wednesday, three Sunni Arab groups — the General Conference for the People of Iraq (search), the Iraqi Islamic Party and the Iraqi National Dialogue — joined forces to field candidates in the election, which was made possible by Iraq's newly ratified constitution.

But an influential group of hard-line Sunni Arab clerics, the Association of Muslim Scholars (search), denounced the constitution and said they will not join the political process.

Those contradictory statements signaled confusion within the minority Sunni Arab community, which forms the core of the insurgency, on how to go forward after it failed to block ratification of the new constitution in the Oct. 15 referendum.

Two U.S. Army soldiers were killed Wednesday when their convoy hit a roadside bomb in eastern Baghdad, the military said. That same day, a roadside bomb and small arms fire struck an Army patrol 37 miles north of Baghdad, killing one American soldier and wounding four, the military said.

The deaths raised to at least 2,004 the number of members of the U.S. military who have died since the beginning of the war in 2003, according to an Associated Press count.

In Baghdad on Thursday, a homicide attacker rammed his car into a U.S. military convoy in Karada, a commercial and residential district, killing one Iraqi passer-by, wounding nine others and damaging two parked cars, said Capt. Mohammed Abdul Ghani. U.S. forces quickly sealed off the area and it was not immediately known if they had suffered casualties.

In Dora, one of the capital's most violent areas, a drive-by shooting by insurgents killed police Lt. Colonel Mahdi Hussein, officials said. A similar attack killed a pedestrian in central Baghdad, said police 1st Lt. Mohammed Khayoon.

Two other Iraqis were killed outside Baghdad.

In the oil-rich Kirkuk city, 180 miles north of the capital, police Lt. Col. Arjoman Saed died of wounds he had suffered the day before from a drive-by shooting in front of his home, said police Brig. Sarhad Qader.

In Fallujah, 40 miles west of Baghdad, insurgents fired a mortar round at the Iraqi army headquarters, leading soldiers to return fire randomly and hit a nearby car carrying three teachers to a school, said police 1st Lt. Assad Hussein Al-Jumaili. One of teachers was killed and two were wounded, he said.

Earlier this week, Iraq's election commission completed an audit on the results of the Oct. 15 constitutional referendum, saying the document had passed by a large margin, thanks to the support of Kurds and majority Shiites.

Many Sunnis opposed the constitution, fearing it could lead to the breakup of the country into semiautonomous regions favoring rival Kurds and majority Shiites.

Sunni Arabs also largely boycotted the Jan. 30 parliamentary election, enabling the Shiites and Kurds to win an overwhelming majority and shape the constitution.

U.S. officials see Sunni Arab participation in the Dec. 15 election as a hopeful sign that more and more members of the community will forsake the insurgency, enabling the U.S.-led coalition to begin drawing down its forces next year.

As Sunni groups were coming together, the Shiite United Iraqi Alliance, which swept most of the parliament seats in January, appeared to be fraying.

Iraq's leading Shiite cleric, Grand Ayatollah Ali al-Sistani, has decided not to endorse the Shiite coalition which ran under his banner in January, according to associates on both sides.

Close associates said al-Sistani's decision reflected his disappointment with Prime Minister Ibrahim al-Jaafari's Shiite-led government. Al-Sistani's endorsement of the Shiite coalition was seen as the principal reason for its success in January.

If al-Sistani does not change his mind, the December election could produce a major realignment of the political landscape. It remains unclear, however, whether political change will produce a quick decline in the insurgency.

On Thursday, al-Jaafari said no coalition ever remains the same over time and that he wants his United Iraqi Alliance to move forward. "I am trying to make it stronger and more active in the coming Parliament to serve Iraq's interests," he told reporters, without providing details.

Meanwhile, U.S. ground and air forces continued to attack insurgents in western Iraq near the Syrian border.

The U.S. military said that an American warplane struck a suspected insurgent safe house there Wednesday and may have killed a senior Al Qaeda in Iraq figure who assisted in smuggling Syrian and Saudi fighters into Iraq.

Without giving details, the military said intelligence sources indicated the figure, identified only as Abu Dua, was inside the house but his body has not been recovered. It added that Abu Dua had also set up religious courts to try Iraqis charged with supporting the Iraqi government and coalition forces.

In the same area, U.S. warplanes killed an Al Qaeda in Iraq insurgent in a safe house in Ushsh village Wednesday, and helicopters apparently killed a militant in a building near Qaim where insurgents had fired at coalition forces, the military said.

Meanwhile, the Iraqi government said another Al Qaeda leader who took part in at least three videotaped beheadings of Iraqis was killed in Mosul on Sunday. Nashwan Mijhim Muslet, also known as Abu Tayir and Abu Zaid, was a senior Al Qaeda member in Mosul wanted for attacks against U.S.-led coalition troops and Iraqi security forces.