The Pentagon reported the first signs yesterday that Yugoslav forces are preparing to withdraw from Kosovo, saying vehicles are moving into place to carry troops out of the embattled province.

While officials stressed that no withdrawals have begun, the preparations reinforced other indications that Yugoslavia is ready for a pullout after several days of uncertainty. The actual beginning of a pullout, in line with Belgrade's commitment last week to end its military presence in Kosovo, has been cited by NATO as the main condition for a halt to the 11-week-old bombing campaign against Yugoslavia.

If Yugoslav troops start exiting in the next day or two, Pentagon officials said, U.S. Marine and Army forces assigned to the vanguard of a peacekeeping force for Kosovo will not be ready to take up positions in the province right away. They remain at least three or four days from reaching the war zone. But a senior officer said British, French and other European forces already in Macedonia could go in first.

The Marines are still aboard three ships in the Aegean Sea off Greece, whose government has delayed unloading in the port of Thessaloniki. Defense officials expressed confidence the 1,900 Marines will be allowed to disembark soon and, once on the ground, could travel to Macedonia and then into Kosovo within 96 hours.

"The Greeks made a public statement yesterday saying that the Marines will be able to leave their ships and deploy through Thessaloniki when necessary -- that there would be no holdup. And we don't anticipate that there will be any problem," said the Pentagon spokesman, Kenneth Bacon.

Bacon announced that 1,700 Army troops in Albania with a fleet of AH-64A Apache attack helicopters will shift to Macedonia and join the Marines. The Army contingent will include eight of the 24 Apache gunships in Albania as well as paratroopers from the 82nd Airborne Division and tanks and other armor from the 1st Armored Division.

Speaking as talks resumed among senior NATO and Yugoslav military officials at a Macedonia border town, Bacon told reporters there is no evidence that any of the estimated 40,000 Yugoslav army, police and paramilitary forces in Kosovo are leaving, nor have Yugoslav troops begun to assemble for a departure. But he cited "a number of indications that the Serbs plan to withdraw," chief among them "signs that they are mobilizing vehicles and other means to transport people out."

Another official said U.S. intelligence intercepted communications from Yugoslav commanders ordering at least some units to make preparations to go.

"We have information that some units are being told to begin planning, not begin doing -- be ready to go, have your stuff together, know how you would do it," said the senior military officer, speaking on condition of anonymity.

U.S. officials remained somewhat vague about just when, after a Yugoslav withdrawal starts, NATO warplanes will stop bombing. Bacon said the North Atlantic Council -- NATO's political body -- will vote to suspend the air campaign once alliance officials can verify that "a certain amount of movement" has taken place. At that point, Bacon added, NATO will issue an "activation order" authorizing the peacekeeping operation, known as KFOR.

Under the withdrawal plan drafted by NATO, Bacon said, Yugoslav forces would assemble in designated areas in Kosovo, then travel on assigned routes through four exit points on the Kosovo border. "The point here is to just elaborate an orderly way for them to get out," Bacon said.

In a report to congressional leaders sent to Capitol Hill earlier this week, President Clinton disclosed that in addition to 7,000 troops the United States has committed to the NATO-led force of 50,000 in Kosovo, another 1,500 U.S. troops will be deployed in Macedonia to support units in Kosovo. Clinton also declined to put a time limit on the peacekeeping operation.

"At this point, it is not possible to determine how long NATO operations in the region will need to continue, nor how long U.S. forces will be needed to assist in refugee relief operations, and therefore how long these deployments will need to be maintained," Clinton wrote.

But the president added that after "an initial stabilization period," the peacekeeping force "will be progressively reduced as the security situation permits and local police forces are established."