Shia officials said Monday that they also agreed to reach out to the country's Sunni Arab community to name the parliament speaker for the 275-member National Assembly that is to convene for the first time since Jan. 30 elections.

On Tuesday, a car bomb targeting a US military convoy exploded on the main road to Baghdad's international airport, police Capt. Thamir Talib said. Four civilians were killed and seven were wounded, including two police officers, he said.

In a report unconfirmed by US officials, witnesses said some US troops were also wounded. When US forces arrived on the scene to evacuate them, another car bomb exploded, wounding more troops. One Humvee was destroyed and two civilian cars were in flames, witnesses said.

A US military spokesman said he was checking into the report.

Another suicide car bomb exploded in northeastern Baghdad, killing one child and wounding at least four people, including a police officer, police Col. Muhanad Sadoun said. The bomber was trying to hit a traffic police patrol but crashed into a tree, Sadoun said.

Separately, a US Marine with the 1st Marine Expeditionary Force died Monday in Anbar, a troubled province that has been a hotbed of guerrilla activity and includes the cities of Fallujah, Ramadi and Qaim, officials said Tuesday.

The Shia clergy-backed United Iraqi Alliance and a Kurdish coalition, which won the two biggest blocks of seats in Jan. 30 elections, agreed last week to form a coalition government with Islamic Dawa party leader Ibrahim al-Jaafari as prime minister. In return, Jalal Talabani will become Iraq's first Kurdish president.

"We discussed the blueprint of the agreement reached Thursday. Some issues were revised and those revisions are still being discussed," alliance member Ali al-Dabagh told The Associated Press.

Al-Dabagh expressed optimism a final deal would be reached soon, but added that even without an agreement "the first session of the National Assembly will be held on Wednesday anyway."