Iraq's president says there will be a two-day delay in the start of an emergency summit of Iraqi leaders to discuss the draft constitution. The summit, which was scheduled to begin Friday, was aimed at resolving major disputes among the country's ethnic and religious groups about the vision of Iraq's future.

A statement from President Jalal Talabani's office did not say why the talks have been postponed until Sunday.

But Kurdish members of the constitution writing committee say the summit had to be delayed so that the autonomous parliament in the Kurdish north could hold an emergency meeting on Saturday to discuss the charter.

Earlier this week, the drafting committee, made up of Shi'ites, Sunnis, Kurds and other groups, vowed to have a constitution ready by an August 15 deadline.

But the committee remains deadlocked over disagreements on a number of issues, which each group considers vital to its vision of the new, post-Saddam Hussein Iraq. The issues include the role of Islam, and how power and oil resources should be shared.

The United States has been pressuring Iraqis to draft a constitution on time, which will pave the way for a national referendum on the charter on October 15 and elections for a permanent government on December 15.

U.S. officials are hoping that the political process will undermine Iraq's insurgency, and allow the United States to substantially withdraw some of its 138,000 troops from the country.

But the top spokesman for multinational forces in Iraq, Air Force Brigadier General Donald Alston, warns that insurgents and Islamic extremists are likely going to try to disrupt that process in the coming weeks and months.

"I feel pretty confident saying that they will try hard to muster their forces as we continue to walk toward the constitutional referendum," said General Alston. "This is a threat to them. Success of democracy in Iraq is failure to the terrorists. So, they are highly motivated to change the trend."

Insurgents in some parts of Iraq have already stepped up attacks against U.S. forces. Some 40 U.S. soldiers and Marines have been killed in action in the past 10 days, including 14 Marines in a single bombing on Wednesday.

The Marines were killed in the Sunni-dominated western Anbar province of Iraq, where the U.S. military has been operating in recent months to shut down insurgent supply routes and the movement of foreign fighters from Syria.

Despite the high number of U.S. casualties, General Alston says the operations have been successful in reducing the threat of suicide car bombings and other activities.

The military spokesman says that there were 13 suicide car bombings in Iraq last week, the lowest weekly number since April.

"We still have suicide car bombs," noted General Alston. "But the numbers that we see indicate that they can't generate the same tempo, and I think it's because we have been able to have some degree of effect interdicting these forces between the Syrian border and Baghdad."

Calling Iraq a country at war, Iraqi Prime Minister Ibrahim al-Jaafari on Thursday announced that his government had plans to strengthen intelligence coordination, and to secure Iraq's porous borders. Mr. Jaafari, however, did not provide any specific details about those plans.