European allies have shown strong backing for the United States as it seeks to recover from the terrorist attacks in New York and Washington. But the NATO allies are cautioning the Bush administration that their support for retaliation against the terrorists does not amount to a blank check.

Although Britain sees itself as America's closest ally and has offered the United States its full support to punish those responsible for Tuesday's attacks, it insists that any retaliation must be based on hard evidence.

France, too, has been strongly supportive of the U.S. call for action to punish the terrorists. But Paris has made it clear that does not mean it will automatically back any retaliatory operation undertaken by the United States.

And Germany, which is believed to have reservations about joining a military action, says it will decide next week whether to assign troops to a NATO strike force.

Despite the unprecedented vote by the NATO council this week to consider the terrorist attack against the United States as an attack against the entire alliance, some allies, like the Netherlands, are skittish about giving Washington carte blanche in its determination to retaliate against the terrorists. The Dutch ambassador to NATO, Nikolaas Biegman, says his government has not yet decided whether to take part in any military operation. "We will be with you mentally, morally and possibly also in concrete terms," he said. "But what it will be at that stage I cannot answer today."

British and French diplomats in Brussels say their countries are ready to provide elite troops to any operation, if that is required. Even Norway, which is believed to be less enthusiastic about a retaliatory strike, says its commitment is firm. Norway's ambassador to NATO, Jakken Biorn Lian, says his country is a team player. "Our resources, of course, are more limited than United States resources, " he said. "But we will certainly put military resources at the disposal of any operation that the alliance will decide. There should be no doubt about that."

European diplomats at NATO say it is still not clear what the alliance's commitment to support America involves. They say many countries are leery of a crusade against international terrorism couched in Biblical terms like good versus evil. And they stress the need to maintain friendships and stability in the Middle East and South Asia.

Former NATO Secretary General Willy Claes says some allies are worried about attacking countries that are suspected of harboring or supporting those responsible for Tuesday's attacks. "It depends on what countries and what could be the consequences of military actions against those countries," said Willy Claes. "Are we speaking about countries that control nuclear weapons, chemical weapons, biological weapons? Yes or no? There's a big difference, you know."

Until a terrorist target is identified, most diplomats at NATO say there is little the allies can do in military terms, other than provide intelligence to assist the United States in its investigation of the attacks.

Though the diplomats say the United States has still not made any specific demands for NATO assistance, they expect Washington to spell out what it wants from its allies in the days and weeks ahead.