Shiite Arab, Sunni Arab and Kurdish framers of Iraq's new constitution struggled Sunday 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 by Monday whether they want an extension of up to half a year. Washington has lobbied hard against any delay, which officials say would set back plans for a significant U.S. troop withdrawal by next spring and shift more momentum in Iraq to insurgents.

Violence across Iraq on Sunday killed at least 25 people, including five Marines killed by bombs and 11 insurgents reported killed by Marines.

Delegates to the constitutional committee said Sunday that 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. Iraqi President Jalal Talabani, a Kurd, went into a meeting with U.S. Ambassador Zalmay Khalilzad and issued a statement afterward demanding that "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 factional lines Sunday, with wide dispute in the various camps over whether the work could be completed on time.

Laith Kubba, spokesman for Prime Minister Ibrahim Jafari'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 Sunday that voting would be limited to Iraqis living inside Iraq.

Insurgent attacks have increased since Jafari's interim government took office in late April with a mandate to develop a constitution.

Gunmen on Sunday attacked the convoy of Deputy Prime Minister Ahmed Chalabi south of Baghdad. The ambush killed one of Chalabi's bodyguards. Chalabi, a repeated target of assassination attempts, was not in the convoy, party spokesman Intifadh Qanabr said.

A car bomb exploded south of Baghdad, killing five civilians. Two other bombings in southern Baghdad killed five U.S. Marines Saturday, the U.S. military said.

U.S. Marines used tanks and jet aircraft to attack insurgents who fired at a patrol with machine guns from a schoolhouse near Haditha, 125 miles northwest of Baghdad. Marines said 11 insurgents were killed.

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

In Baqubah, one Iraqi soldier was killed and three were wounded by gunmen after they left their jobs at a former U.S. base, a commander for Diyala province told the AP.

U.S. Ambassador Zalmay Khalilzad, right, and President Jalal Talabani meet to discuss the Iraqi constitution.