KIEV, Ukraine (AP) _ Ukraine and the United States have finalized details on the usage of Ukrainian airspace by American military transport planes, officials said Saturday.

The consultations, which ended Friday, concerned the rules covering the entrance of U.S. aircraft into Ukraine's airspace, accompanying flights by Ukrainian planes, air traffic control and potential emergencies, said Mykola Palchuk, first deputy head of the Ukrainian armed forces' general staff.

If needed, U.S. aircraft will fly over Ukraine at an altitude of no less than 30,030 feet, and may use three military airfields and several air corridors, he said, according to the Interfax news agency.

``The planes might leave us in any direction and use the corridors for return flights,'' Palchuk said.

The officer declined to cite any possible date for such flights. He said only that the planned U.S. retaliatory strike for Sept. 11 terror attacks in New York and Washington was a ``complex and unorthodox'' operation.

Officials from Ukraine's aviation control bodies and the Defense Ministry were involved in consultations with the U.S. side, he said.

Earlier in the week, Ukraine's National Security and Defense Council agreed to let U.S. military cargo aircraft fly across the country's airspace. Under Ukrainian law, the U.S. planes are not to carry nuclear, chemical or biological armaments or their components.

The decision does not provide for flights by fighter jets and helicopters, or for the transportation of tanks and large-caliber artillery pieces, which would require special approval by the Ukrainian parliament.