NATO's drive to modernize its military to confront new threats from terrorists or rogue states tops the agenda at a meeting starting Tuesday of alliance defense ministers that will be overshadowed by the Iraq crisis.

U.S. Defense Secretary Donald H. Rumsfeld is expected to outline plans for a new rapid response force of about 20,000 U.S, Canadian and European combat and support troops capable of deploying on as little as one week's notice.

Officials said it could comprise elite ground troops, AWACS radar planes, shared allied intelligence, naval units and chemical-biological defenses.

"It's one more instrument we can use in an increasingly dangerous world," NATO Secretary- General George Robertson told reporters. "We look forward to hearing the details."

The new force proposal is part of wider talks for an overhaul of NATO's military in the wake of Sept. 11. The aim is transform an alliance established more than 50 years ago to deter a Soviet attack into a mobile, flexible coalition to confront new threats.

NATO itself is unlikely to play a direct role in any U.S.-led action against Iraq. Instead, Rumsfeld is expected to seek support among allies for military action against Iraqi leader Saddam Hussein.

Animosity between the German and American governments over the Iraq in recent days underscored the depth of divisions within NATO the issue.

U.S. officials were disturbed by Chancellor Gerhard Schroeder's emphatic opposition to American military action to oust Iraqi leader Saddam Hussein during campaigning for parliamentary elections which Schroeder's governing coalition won Sunday. Washington was particularly incensed by a German minister's reported remarks comparing President George W. Bush to Adolf Hitler by using war to distract from domestic problems.

Rumsfeld on Monday criticized the anti-U.S. tone of the elections saying it had the effect of "poisoning" U.S. relations with a longtime ally.

Other NATO allies are skeptical about an attack on Iraq, and American officials stressed it was too early to request specific military contributions from the other 18 allies.

However, diplomats said they expect the Americans will want to discuss options for possible allied support if war breaks out -- ranging from combat units to fight alongside American forces, to peacekeeping in a post-Saddam Iraq or access to ports, bases or air space.

The meeting Tuesday and Wednesday also gives NATO a first chance to discuss the new U.S. national security strategy unveiled Friday by President George W. Bush which includes a strike-first policy against potential threats.

Many European allies have misgiving about such a doctrine of pre-emptive attacks. While Britain is largely supportive, France and Germany are wary.

Rumsfeld should find wider support for Bush's call for the alliance to "build a capability to field at short notice, highly mobile, specially trained forces whenever they are needed to respond to a threat."

Responding to warnings that NATO risks slipping into irrelevance unless they modernize their militaries, Britain, France, Germany and other allies are stepping up defense spending as part of an alliance push to upgrade its weaponry.

The defense ministers are due to fine-tune those plans in Warsaw, aiming to fill gaps in the alliance arsenal such as safeguards against germ warfare, poison gas or nuclear attacks; anti-missile defenses; big transport planes that can get soldiers and equipment to trouble spots quickly; ground surveillance planes; precision-guided munitions and air-to-air refueling.

President Bush and the other allied leaders are due to approve the modernization plan at a summit meeting Nov. 21-22 in Prague, fixing firm deadlines for each ally to meet their targets for acquiring the new equipment.

Russian Defense Minister Sergei Ivanov will join the meeting Wednesday.