BRUSSELS, Belgium - NATO allies agreed yesterday to provide the United States with all the assistance requested as it prepared a military response to the attacks on New York and Washington.

The 18 other allies agreed to U.S. requests for unlimited use of their airspace; access to ports, airfields, refueling facilities and NATO airborne early-warning aircraft; extra security for U.S. forces in Europe; intelligence sharing; and replacement of any troops that might be moved from the Balkans.

The nations also agreed to stage a naval show of force in the Eastern Mediterranean "to provide a NATO presence and demonstrate resolve," an official statement said.

"These decisions clearly demonstrate the allies' resolve and commitment to support and contribute to the U.S.-led fight against terrorism," NATO Secretary-General George Robertson said at a news conference.

The swift acceptance of the full list submitted Wednesday after the allies invoked the mutual defense clause of NATO's founding treaty was a powerful signal of political support for the United States.

NATO activated Article V, under which an attack on one ally is treated as an attack on all, after the United States laid out detailed evidence Tuesday implicating Saudi-born Islamic militant Osama bin Laden and his Afghan-based al-Qaida network in the Sept. 11 suicide airliner attacks.

Robertson made clear he did not expect NATO to be directly involved in collective military action, saying it was "open to the United States to act on its own, or to do so in association with any group of states."

The allies pledged to increase security for U.S. and allied facilities on their territory and provide assistance to states "which are or may be subject to increased terrorist threats as a result of their support for the campaign against terrorism."

This appeared to be a veiled call on NATO nations to help protect and reward countries such as Pakistan, Oman, Uzbekistan and Tajikistan that face political and security risks from providing the United States with vital assistance and bases.

Robertson named no countries but said: "It's a statement of solidarity, a recognition that some countries may face problems if they take a firm stand."

A senior NATO diplomat stressed that the assistance pledged by the allies was open-ended.

"We are not restricting ourselves to geographical limits, to time limits or to target limits," he said. "This is a broad campaign against terrorism. ... Today's decisions are blanket."

A European diplomat said that while some of the measures, such as granting blanket overflight clearances, could be taken instantly, others would require detailed military planning.

Attack could be days away

France's defense minister said yesterday in Paris that U.S. military retaliation for last month's attacks isn't likely for several weeks.

Alain Richard said many key decisions by nations participating in the U.S. anti-terrorism campaign had not been made and should not be made in haste.

But some experts said the time window for military action appeared to be narrowing, with several indicators pointing to a possible strike as soon as soon as next week.

A host of factors including politicians' travel plans, the humanitarian situation in Afghanistan, public opinion, the weather and Muslim holidays all point to a short window of opportunity for action between Monday and the middle of next month.

Food airdrops expected