There has been no "substantial compliance" by President Slobodan Milosevic to pull his forces out of Kosovo, according to NATO officials. The pullout is demanded by the West to make it safe for thousands of ethnic Albanian civilians to return to their homes before winter.

NATO Secretary-General Javier Solana flew to Belgrade with the Western military alliance's top generals, who quickly signed an agreement with the Yugoslav army permitting unarmed surveillance flights over Kosovo.

"We see no evidence of substantial compliance by Milosevic. That's the bottom line," Solonal told reporters.

Air strikes will be launched against Yugoslav targets Saturday unless there is incontrovertible evidence that compliance was guaranteed. Intelligence reports show Serbian troops and police still in Kosovo.

In Washington on Thursday, the White House said Milosevic was still not meeting Western demands.

"Obviously there's a range of things that need to be done to come into compliance," White House spokesman Joe Lockhart said.

That message would be delivered by Solana who was accompanied to Belgrade by NATO's Supreme Commander, U.S. General Wesley Clark, and General Klaus Naumann, chairman of NATO's military committee.

Clark will be seeking cast-iron assurances that there will no threat to NATO aircraft or 2,000 unarmed members of a verification mission on the ground.