BAGHDAD, Iraq – A suicide car bomber struck an American convoy waiting at an intersection yesterday in Baghdad, killing seven people – including one American soldier – and wounding more than 90. More than a dozen others died in scattered attacks across the capital.

Also, an American Marine assigned to the 2nd Marine Division was killed Monday by small-arms fire in Ramadi, 70 miles west of Baghdad, the American military said. The deaths brought the number of American service members killed in Iraq this month to at least 32.

Violence raged as Iraqi political leaders showed little sign of compromise less than a week before a deadline for approving a new constitution. Faction leaders conferred for about four hours last night, hoping to overcome their differences and produce a charter by Monday. Participants said the talks focused on Kurdish demands for a federal state, and although some progress was made, there was no final agreement on the issue. More talks were set for today.

The American convoy was stopped at a busy intersection when a driver detonated a vehicle packed with explosives, the American Army said. Six Iraqi civilians also were killed; scores of Iraqis and two American soldiers were wounded.

America hopes progress on the political front, including adoption of a constitution, will help deflate the Sunni Arab-led rebellion and enable the Americans and their partners to begin withdrawing troops next year. “It’s important that they stay with their timetable” on the constitution, Defense Secretary Rumsfeld said yesterday. “This will be a critical step in persuading the majority of the Iraqis that the new Iraq is worth fighting for, that they have a stake in it.”

Mr. Rumsfeld told Pentagon reporters that the constitution “could well turn out to be one of the most powerful weapons to be deployed against the terrorists” and the insurgents are “determined to stop the constitutional process through terror and intimidation.”

Late yesterday, representatives of political factions met for a second round of talks aimed at breaking the deadlock over the constitution, which the parliament must approve by August 15. Talks were postponed Monday by a severe sandstorm. The constitution also needs approval from voters in an October 15 referendum. Passage would lead to elections in mid-December.

At the beginning of the meeting, presidential spokesman Kamran Qaradaghi told reporters the latest talks would focus on federalism, distribution of wealth, and the elections law. Kurds demand that Iraq be transformed into a federal state so they can continue to run their autonomous mini-state in the north. Sunni Arabs oppose federalism because they fear the Kurds want to secede.

A Kurdish parliament member, Mahmoud Othman, said that during the meeting, American Ambassador Zalmay Khalilzad repeatedly called President Talabani and Parliament Speaker Hajim al-Hassani for updates – a sign of American pressure for a deal.

In other developments:

* American troops yesterday killed four insurgents trying to plant a roadside bomb in the city of Ramadi, police Lieutenant Mohammed al-Obeidi said.

* Violence targeting Iraqi police left 10 officers dead, including five policemen slain while sleeping in their car. Lieutenant Colonel Ahmed Aboud said the men had spent the night on patrol and were waiting for replacements.

* Late yesterday, gunmen killed an Iraqi Cabinet employee, Abbas Ibrahim Mohammed, in Baghdad. In addition, three civilians were killed in a mortar attack, police said.

* American and Iraqi forces killed two insurgents and arrested 22 others in northern Iraq, the military said.

* The mayor of Baghdad, Alaa al-Timimi, was fired, and responsibility for managing the city transferred to the provincial governor, a government spokesman, Laith Kubba, said.