The 100,000-plus allied troops occupying Iraq will begin their withdrawal within "a matter of days" after the United Nations approves a formal cease-fire, Pentagon officials say.

"We want to leave as quickly as possible - it will be a short period of time. It's not going to be kind of prolonged, dragged-out withdrawal once the terms of the cease-fire are in place," said a senior Pentagon official.While the allies' hold on southeastern Iraq has served as the primary bargaining chip in forcing Iraqi acceptance of the U.N. resolution, U.S. officials believe economic sanctions will prove "the main lever" in forcing Saddam Hussein's compliance.

Final action on the U.N. resolution could come this week. While some issues remain unresolved, "we're very hopeful of passage," the official said. "It's proceeding very well."

"I can assure you that not much has been left untouched in this resolution, in terms of anything that would give Iraq the power, the wherewithal to create trouble," said the official, who spoke on condition of anonymity. "They are the defeated country; I'm not sure they have much choice" but to accept the U.N. terms.

The proposed U.N. resolution is designed to clear the way for a permanent cease-fire in the gulf war. It requires:

- Iraq to destroy all its remaining chemical, biological and nuclear weapons and forswear future development or acquisition of such arms. Nuclear materials that could be used for weapons would be destroyed or removed by the International Atomic Energy Agency.

- Iraq to be liable for damage, including environmental harm, resulting from its invasion of Kuwait. It would have to cooperate with the International Red Cross in repatriating Kuwaitis, forswear international terrorism and vow to respect its 1963 boundary with Kuwait.

- Establishment of a U.N. military observer force monitoring a demilitarized zone reaching six miles into Iraq and three miles into Kuwait.

Some elements of the resolution - such as the reparations - could take years to fulfill, the official said, but large numbers of U.S. ground forces don't have to remain in the region until that is accomplished.

At the end of the week, 398,500 U.S. military men and women were deployed in the gulf region, with thousands returning home daily.

U.S. naval forces are still enforcing the sanctions against Iraq, and a beefed-up presence is expected to remain in the gulf region.

Defense Secretary Dick Cheney has repeatedly said the administration has no interest in permanently stationing ground troops in the gulf.

Once the cease-fire is in place, "we're talking a matter of days" before a troop withdrawal could begin, said the official, a specialist on Mideastern affairs. "It's not going to take us months to get out of there, if everything falls into place."

Some consideration must be given to an orderly and safe move over lands that had recently been battle zones, and where unexploded ordnance is a common occurrence.

In another interview, a senior military officer said the estimated 100,000 ground troops would be removed in a staged process that could take several weeks.

Since the XVIII Corps has withdrawn to Saudi Arabia for redeployment, the Europe-based VII Corps has taken its place, moving in heavier tanks and artillery forces.

Those units need some time to pack up their equipment and prepare for the trip home, the officer said.

"We moved in on rush-hour rates. We'll take a bit more time getting out," he said.

French and British combat troops also have held their posts in the occupied zones and have agreed not to move until the allied forces begin their move. Their smaller numbers mean an earlier departure, leaving only U.S. forces in the region for a time, the officer said.

The widely dispersed combat units, which have stretched scores of miles along the Euphrates River and southward toward Kuwait, will probably consolidate at several points inside Iraq for the drive southward to Saudi Arabia, the officer said.

The Air Force will continue to fly combat patrols to ensure no threat arises during the withdrawal, a role the Saudi air force may take over at some point, the officer said.

No combatants or allied forces from the war would participate in the U.N. force, and the many inspections will be handled by international agencies experienced in dealing with issues such as nuclear weapons and production capabilities, the official said.

"We should not have a direct involvement in the inspections. It all has to be done under international supervision," the official said.

It will be in the West's interests to have Saddam remain in power long enough for the resolution to be approved, since he is "perceived as such a bad guy," the official said.

If the Iraqi president were toppled amid the current rebellion, there is some concern that strong international support for the U.N. resolution might erode, the official said.