By the BBC's Jonathan Marcus

Nato Secretary-General George Robertson has issued an urgent call for the alliance's European members to significantly improve their defence capabilities.

Speaking at a security conference in Munich, Lord Robertson pointedly stressed that, without such improvements, European forces would be unable to operate alongside the US military, limiting the influence of European governments on US policy.

US allies must show a new willingness to develop effective crisis management capabilities

Lord Robertson

So far, Nato's practical role in the war against terrorism has been minimal, although Nato did dispatch radar-carrying aircraft to the US to assist in air defence and Nato troops have also detained alleged Islamic militants in the Balkans.

But after taking the unprecedented step of declaring the 11 September attacks in New York and Washington as an assault on the alliance as a whole, Nato largely sat out the war in Afghanistan on the sidelines.

US critics

Lord Robertson insisted that the journalists and leader writers who were speculating about Nato's future were wrong, but he did admit that, if the alliance was to remain relevant, change was needed.

Robertson: Growing technological gap

On paper, he said, the Europeans' capabilities were impressive - but in practice hardly any European country could deploy usable and effective forces in significant numbers outside their borders, and sustain them for months or even years, as the alliance needed to do today.

This, he warned, would inevitably have implications for Nato cohesion and gave fuel to US critics of Europe's military incapability.

"If we are to ensure that the United States moves neither towards unilateralism, or isolationism, all the known US allies, Europeans and Canadians, must show a new willingness to develop effective crisis management capabilities," Lord Robertson said.

'Vital coalition'

The secretary-general's fear is that a growing technological gap between America and its allies could lead to a growing political gap as well, as Washington relies upon its own hi-tech capabilities to go it alone in future military operations.

Russia claims Bin Laden's influence in Chechnya

He believes that "the world's largest permanent coalition", as he described Nato, still has a vital part to play.

Indeed, many governments are eager to attach themselves to the anti-terrorist efforts.

The Russian defence minister Sergei Ivanov spoke at length to the conference on this subject, placing Russia's problems in Chechnya firmly in the context of the international struggle against terrorism, and insisting on the links between Chechen separatists and Osama bin Laden.

In Moscow's view, its struggle in Chechnya is just one aspect of a much broader phenomenon.