The top U.S. general in Iraq says the country's new constitution has created a divisiveness that makes it more difficult to predict when coalition forces might be able to leave the country. In addition, the general says, he wants to defeat al-Qaida and other foreign elements before handing security control to Iraq's new forces.

At a news conference on Friday, General George Casey expressed concern about the Iraqi draft constitution, on which Iraqis will vote on October 15. And he said that concern has made him more cautious about evaluating when it might be possible to begin withdrawing foreign troops from Iraq. Earlier in the week, he changed his prediction for the start of an allied withdrawal from the early part of next year to later in the year.

"This constitution has come out and it didn't come out at the national compact that we thought it was going to be. And there's a little division there. It's not a bad constitution, but there's a little divisiveness because of that. And that caused the situation to change a little bit," he said.

Many Iraqi Sunnis oppose the constitution, and many of them have registered to vote in the referendum. General Casey said on Thursday that the next 75 days will be crucial in determining when he can begin to reduce the number of U.S. and other coalition forces in Iraq. That period covers the constitutional referendum and the expected elections for a new government in December.

Defense Secretary Donald Rumsfeld said that period will expand depending on how long it takes to actually form a new Iraqi government after the election, and how much disruption that causes in the key defense and interior ministries.

General Casey says that while the political process plays out, and while he works to improve the readiness of Iraq's new security forces, the coalition must focus on destroying the al-Qaida terrorist network in Iraq. He and other officials have said that al-Qaida and its foreign fighters are a small part of Iraq's insurgency, but are also its most deadly part.

"We need to defeat these guys in the next six to 12 months, restore Iraqi control of the borders, keep them from bringing in the suicide bombers and the foreign fighters, so that after these elections the Iraqis have the opportunity to deal with the former regime elements," he said.

General Casey said the remnants of the Saddam Hussein regime are the larger but less effective part of the Iraqi insurgency, and he believes that, unlike the foreign fighters, the Iraqi insurgents can be brought into the political process over time.