The United States has challenged European Nato countries to increase their spending on defence - and called on them to take a greater share of the burden of defending Europe.

American Defence Secretary William Cohen also questioned whether European members had the political will to meet some of the security goals they have set themselves.

Commitment

Speaking at the Munich Conference on Security Policy, he told European allies they must spend more and make a sustained political commitment in order to achieve their goal of closing the technological gap with US military forces.

He told the conference: "You cannot continue to cut budgets.

"You cannot have a situation in which one country bears a disproportionate burden."

Combat missions

Mr Cohen referred to Nato's Kosovo campaign where the US flew half of all combat missions and two-thirds of all air support missions during the 78-day conflict.

His sentiments were echoed by Lord Robertson, the former British defence minister, who is now Nato's secretary-general.

He told the conference earlier: "It is neither fair nor politically sustainable to ask the United States to continue to assume a disproportionate share of the costs and the burden of addressing security challenges in Europe."

Defence correspondent Jonathan Marcus says senior US Congressional figures are increasingly alarmed that the Europeans have not provided promised money or sufficient civilian police units for Kosovo.

Of the 1,800 or so already deployed, almost one-third are American - hardly, say the American critics, a demonstration of the Europeans taking the destiny of the continent into their own hands.

Modernise militaries

And Mr Cohen said many European governments had said for years they wanted to modernise their militaries but had been satisfied instead to let the US take the lead.

"My fear is that we will see European nations constructing a new bureaucracy without achieving truly integrated military forces."

During a break in the conference, Mr Cohen and British Defence Minister Geoffrey Hoon signed a declaration of principles to establish the basis for improving US-British co-operation in the defence trade.