President Bush last night threw down the gauntlet to the United Nations: either it curbs Saddam Hussein or the US will destroy him.

In a hard-hitting speech to the General Assembly in New York, the president said Saddam had to be stripped of his weapons of mass destruction or ousted from power.

World leaders who had been reluctant to confront the threat must "move deliberately and decisively to hold Iraq to account".

Mr Bush said: "The just demands of peace and security will be met - or action will be unavoidable. We must stand up for our security and for the permanent rights and hopes of mankind."

The president reeled off a list of accusations against Baghdad while Saddam's UN ambassador Mohammed Al-Douri listened impassively. They included:

l Iraq would be able to build a nuclear weapon within a year if it acquires fissile material,

l Iraq maintains stockpiles of chemical weapons; is rebuilding and expanding facilities capable of producing more.

l UN inspectors believe Iraq has produced two to four times the amount of biological agents it declared.

* Iraq has provided a haven for al-Qaida terrorists.

"If an emboldened regime were to supply these weapons to terrorist allies, then the attacks of September 11 would be a prelude to far greater horrors," said Mr Bush.

He made his case to the 190 UN nations against the backdrop of widespread hesitation among allies - and US politicians - to use force against Baghdad.

UN Secretary-General Kofi Annan, speaking before Mr Bush, cautioned the US against taking action without Security Council backing.

But he also warned Saddam that time is running out and if Iraq is defiant, the Security Council "must face its responsibilities".

Mr Bush said: "Iraq has answered a decade of UN demands with a decade of defiance. All the world now faces a test - and the United Nations, a difficult and defining moment.

"Are Security Council resolutions to be honoured and enforced, or cast aside without consequence? "

He made clear that if the UN failed to rein in Saddam, the US would use force to remove him from power.

US Secretary of State Colin Powell will work today with the four other permanent members of the Security Council - Russia, China, France and Britain - on a resolution that would set a deadline for Iraq to comply with demands that it admit weapons inspectors.

A senior US official did not say what deadline would be set in a new resolution. But he did say the resolution would demand compliance within weeks, not months.

Meanwhile, after a day of intense discussions with other party leaders, Tony Blair announced that parliament would be recalled on September 24 to debate Iraq.

The Prime Minister threw his weight fully behind Mr Bush and won strong support from Tory leader Iain Duncan Smith.