The US has said it sought help from individual allies in its "war on terrorism" but did not envisage collective NATO military action in response to the attacks on New York and Washington.
The US Deputy Defence Secretary, Mr Paul Wolfowitz, won unanimous applause from NATO defence ministers for what the Secretary General, Lord Robertson, called the "measured" US approach to the crisis. European allies praised President Bush for working patiently to build a global coalition to fight terrorism rather than lashing out in retaliation for the September 11th attacks.
Mr Wolfowitz said many allies were participating in what would be a sustained campaign to isolate "terrorists". He singled out Britain, France and Turkey.
NATO's September 12th declaration that if the attacks were initiated from abroad, they would be considered an assault on all allies, was "a very powerful basis for a variety of individual requests to individual countries", Mr Wolfowitz said.
"If we need collective action, we'll ask for it. We don't anticipate that at the moment," he said. Mr Wolfowitz sought to play down expectations of imminent US military action.
Lord Robertson said because of the attacks, NATO would have to start "thinking the unthinkable".
"Some of the threats that remained in the realm of almost unbelievable fiction now have to be treated as credible threats for which we have to have credible capabilities and strategies," he said.