Testifying at her Senate confirmation hearing, Ms Rice offered a softer image of an administration often criticised for its pre-emptive military action in response to the September 11, 2001 terror attacks.

“Our interaction with the rest of the world must be a conversation, not a monologue,” Ms Rice told the Senate Foreign Relations Committee as she made her case for moving from national security adviser to secretary of state.

Ms Rice defended the US military moves into Afghanistan and Iraq as “necessary and right,” but signalled a more conciliatory approach to countries opposing Washington’s tough line.

“Now is the time to build on these achievements to make the world safer and to make the world more free,” she said. “We must use American diplomacy to help create a balance of power in the world that favours freedom.”

She named Belarus, Cuba, Iran, Myanmar, North Korea and Zimbabwe as “outposts of tyranny” to which the US must help bring freedom.

While citing NATO, the European Union and democratic allies as “our strongest partners” in battling terrorism, Ms Rice also made it clear the US was ready to go it alone if its security interests were at stake.

Condoleezza Rice, one of President George W Bush’s closest aides, was expected to face little trouble getting past the committee and the full Senate later this week to win confirmation as the successor to Colin Powell.

In a heated exchange, California Democrat Senator Barbara Boxer argued that the Bush administration had shifted its justification for the war in Iraq because it had failed to find stocks of biological and chemical weapons it had cited as the reason for invading.

“It wasn’t just weapons of mass destruction,” Ms Rice told senators, saying former Iraqi leader Saddam Hussein supported terrorism, attacked Kuwait and Israel and needed to be removed given the new US threat perception after the September 11 attacks.

While staunchly defending the move to invade Iraq, she conceded US forces had run up against “unforseen circumstances” and a stubborn insurgency impeding democratic development.

But she was unable to say when the 150,000 US troops in Iraq nearly two years after the invasion would start to go home.

Ms Rice also vowed to make ending the Israeli-Palestinian conflict a priority, but was non-committal on prospects for dispatching a special US envoy. She said peace was ultimately up to the parties in the region.