BAGHDAD, Iraq — Shiite Arab, Kurdish and Sunni framers of Iraq's new constitution struggled yesterday over whether to ask for more time for their work, facing a deadline in 15 days and with many fundamental questions still unresolved.

Delegates must announce today whether they want an extension of up to a half-year. Washington has lobbied hard against any delay, which it says would set back plans for a significant U.S. troop withdrawal by spring and shift more momentum in Iraq to insurgents.

Violence across the country yesterday killed at least 20 people — including 11 insurgents reported killed by Marines. The Marines used tanks and jet aircraft to attack insurgents who fired at a patrol with machine guns from a schoolhouse near Haditha, northwest of Baghdad.

Delegates to the constitutional committee said yesterday they had begun talk of a 30-day extension, despite adamant statements from Western and Iraqi officials just the day before that the draft would be completed by the Aug. 15 deadline.

The proposal for a delay appeared to catch at least some U.S. officials by surprise. President Jalal Talabani, a Kurd, went into a meeting with U.S. Ambassador Zalmay Khalilzad and later issued a statement demanding "maximum efforts be exerted" to finish the work on time.

Any delay would have "serious implications to the security situation," said Barham Salih, a Cabinet minister.

The delegates have to decide on several complex issues including a Kurdish-led push for a federal system, the extent of religious influence, Kurdish territorial demands, and a new electoral system. The name of the country itself remains unsettled after a summer of debate, with Shiites seeking a variation that includes "Islamic Republic."

The debates on any delay and how to handle it crossed faction lines yesterday, with wide dispute in the various camps over whether the work could be completed on time.

Laith Kubba, spokesman for Prime Minister Ibrahim al-Jaafari's Shiite-led government, joined Sunni delegates in suggesting the constitution be approved with the hardest decisions put off. "Which means the issues they disagree on will be discussed in a much healthier atmosphere than now," Kubba said.

Iraqis are scheduled to vote on the draft constitution in October and on a new government in December. Adil Lami, head of the electoral commission, announced yesterday that voting would be limited to Iraqis living inside Iraq.

• A car bomb exploded yesterday south of Baghdad, killing five civilians and wounding 10, including two policemen.

• Gunmen yesterday attacked the convoy of Deputy Prime Minister Ahmad Chalabi south of Baghdad. The ambush killed a Chalabi bodyguard. Chalabi, a repeated target of assassination attempts, was not in the convoy, party spokesman Intifadh Qanabr said.

• Gunmen in Baghdad opened fire on a minibus carrying Justice Ministry employees who work in the prisons department, wounding two. Insurgents frequently target buses carrying government employees or Iraqis working on U.S. military bases.

• In Kirkuk, assailants opened fire on a truck carrying employees of the local health administration, killing one and wounding two, police said. Gunmen also killed an Iraqi translator for U.S. troops in the south, police said.

• In Baqouba, gunmen killed one Iraqi soldier and wounded three others after they left their jobs at a former U.S. base, a Diyala provincial commander said.

Information from The Associated Press is included in this report.