America gave notice yesterday that it was ready to act alone against Iran and North Korea if European countries did not co-operate in stopping them from developing nuclear weapons.

"If we do not want a 'Made in America' solution, let's find out how to resolve the issues of North Korea and Iran," declared Condoleezza Rice, the US national security adviser, during a visit to London.

She tried to play down the prospect of a war against Iran, saying: "We do not ever want to have to deal with the proliferation issue as we did in Iraq." But her comments had strong echoes of the blunt talking that surrounded the debate before the Iraq war.

Accusing Iran of seeking secretly to build nuclear weapons, and vowing that North Korea would not be allowed to "blackmail" the world with threats to resume its nuclear programme, Miss Rice said the US sought international co-operation.

She said Iran's programme was best dealt with by convincing the nation to agree to intrusive inspections by the International Atomic Energy Agency. North Korea was best addressed by regional powers exerting pressure.

But Miss Rice, who leaves for the Middle East today, pointedly did not rule out military action. "The avoidance of war is not in itself a final goal," she said. "Sometimes one has to fight wars to deal with tyrants."

Later Miss Rice added: "We want a multi-lateral solution. But we do want a solution.

"Post 9/11, the sense of urgency to have solutions to these problems has grown. The absence of action is not a solution. Sometimes multi-lateralism is code for not acting."

Addressing the International Institute for Strategic Studies, Miss Rice delivered a thinly-veiled attack on Jacques Chirac, the French president, and his desire to create a "multi-polar" world in which Europe acts as a counter-weight to America.

She described the notion of competing poles as a destructive throw-back to European rivalry in the 19th century.