Led by US Vice-President Dick Cheney, several senior US administration officials stepped up the case yesterday for a pre-emptive strike against Iraq, focusing on the prospect of President Saddam Hussein acquiring nuclear weapons in the near future.
The Iraqi leader was "actively and aggressively" seeking to build a nuclear bomb to add to his stockpiles of biological and chemical weapons, Mr Cheney told CNN, citing unspecified intelligence gathered over the past 12 to 14 months. "And increasingly, we believe the United States will become the target of those activities." he said.
Mr Cheney's claim followed a report in yesterday's New York Times quoting unnamed administration officials alleging that in the past 14 months, Iraq had sought to buy thousands of specially designed aluminium tubes that were possibly intended as components for a process to enrich uranium.
On Thursday, President Bush will go to the United Nations in a last ditch attempt to build a coalition for US action against Iraq, before seeking an enabling resolution from the UN Security Council. He is expected to call for the enforcement of a 1991 ceasefire arrangement with Iraq that mandates complete disarmament of all weapons of mass destruction.
Mr Bush is expected to tell the UN that, if necessary, the United States will act on its own to remove Saddam, and that there is no time to waste. A leaked early draft of his speech refers to Iraq as a "ticking timebomb".
Mr Bush is reported to be considering a UN Security Council resolution, possibly to be proposed by the UK, that would set a deadline for Iraq to open its weapons sites to unfettered inspection, and to take punitive action if the Iraqi president refused.
Today, Mr Bush travels to Detroit where he will lobby Canadian Prime Minister Mr Jean Cretien for support. Mr Cretien has said he is not convinced of the case for a pre-emptive strike and that the US must show proof of the danger posed by Saddam Hussein.
Other key allies including France, Germany and Russia, oppose the use of force against Iraq. Mr Bush telephoned Russian President Vladimir Putin and French President Jacques Chirac at the weekend. Both reportedly reaffirmed their opposition to US military action. He also called China's President Jiang Zemin.
Mr Bush's closest ally on the Iraq question, the British Prime Minister, Mr Blair, pledged his support for the US when he met the President at Camp David on Saturday, but insisted that "the UN has got to be the way of dealing with this issue, not the way of avoiding dealing with it".
The US and Britain wanted the international community to form a broad coalition against Saddam that must achieve results and not preserve the status quo, but "the policy of inaction is not a policy we can responsibly subscribe to", he said, as he joined Mr Bush for four hours of talks and dinner at the secluded presidential retreat in Maryland's Catoctin mountains.
At Camp David, Mr Blair referred to a "new report" from the UN-affiliated International Atomic Energy Agency to underline the urgency of the situation - an apparent reference to US and UK press reports on Friday that satellite photographs obtained by the agency showed new construction at several locations identified as nuclear-related sites dismantled during pre-1998 inspections.
Mr Bush said UN weapons inspectors concluded before leaving Iraq in 1998 that Saddam was "six months away from developing a weapon", and also cited satellite photos from the agency showing unexplained construction at Iraqi weapons sites.
However a spokeswoman at IAEA headquarters in Vienna, said the agency had issued no new report and that the newspaper accounts referred to commercially available pictures published in July when they received little media interest.
"There is nothing new," the spokeswoman said.
The US Secretary of State, Mr Colin Powell, fell into step with administration colleagues yesterday, telling Fox TV that whatever the UN decided, Mr Bush will reserve the right to go it alone against Iraq.
"When you can intercept a terrorist act that is heading your way or you can deal with a regime or a situation before it comes to a crisis level and threatens you, then it is an option that you should keep in mind and on the table," said Mr Powell, regarded as the least hawkish member of the administration.