Tens of thousands of people have attended anti-war rallies across the United States on the eve of a key speech by President George W Bush putting his case against Saddam Hussein.

The protest in New York was the largest gathering of American opponents to conflict since the start of the current threats of military action against Iraq, which Washington accuses of developing weapons of mass destruction.

It was one of more than 25 rallies organised by the Not In Our Name group to coincide with the first anniversary of the start of the US-led military campaign in Afghanistan.

Efforts to win international support by both the US and Iraq have meanwhile continued, and Iraqi President Saddam Hussein issued a defiant statement saying he would never give up his leadership.

- Stars speak out

The estimated 20,000 people who gathered in New York's Central Park were joined by Hollywood stars to speak out against any future war.

Actress Susan Sarandon asked: "Do we the people really want to be a new Rome that imposes its rule by the use of overwhelming force whenever its interests are threatened?

"Even perceived potential threats? We do not want endless warfare."

The crowds in New York, along with similar gatherings in Chicago, Los Angeles, San Francisco, Seattle and many smaller communities, also recited a "pledge of resistance" devised by Not In Our Name.

It includes: "Not in our name will you invade countries, bomb civilians, kill more children, letting history take its course over the graves of the nameless."

- Political support

In New York, Ms Sarandon called on people to back US politicians who opposed the war, but the Bush administration picked up new support from one of the most senior members of Congress.

Senator Majority Leader Tom Daschle, who had withheld his backing for a Congressional resolution giving Mr Bush war powers, said on Sunday that he did believe a first strike against Iraq could be merited.

While pushing a diplomatic solution, he told NBC's Meet the Press programme: "We ought to, if no other option is available... use pre-emptive force unilaterally if necessary."

He added that he thought the Senate would pass overwhelmingly a resolution authorising President Bush to attack Iraq.

- International action

In his speech on Monday, Mr Bush is expected to try to maximise support for his policy from US politicians and citizens as well as international leaders.

On Saturday, he warned war might be "unavoidable".

British Foreign Secretary Jack Straw also begins a tour of the Middle East on Monday to garner support for action from the countries in the region who could be most affected.

Mr Straw's four-day trip to Egypt, Iran, Jordan and Kuwait, follows efforts by the Iraqis to persuade their neighbours to back them, or at least not the US policy which envisages the toppling of the ruling regime.

Hussein remains defiant, vowing never to quit his leadership of Iraq, according to comments released on Sunday.

He denounced Washington's demands for a new United Nations resolution calling on Iraq to reveal the state of its weapons production or face invasion and said his country would be victorious in any showdown.

"We did not choose the battle with the enemy and this means we did not prepare ourselves to confront the enemy but the enemy is preparing itself to attack us...and leave us as slaves without identity, honour or money," he was quoted by the Iraqi News Agency as saying.