The more measured approach from Bush comes in the context of the administration's concern to win congressional approval for the option to deploy US forces against Iraq. The US has also been working hard to build a consensus among the five permanent members of the UN Security Council on a new resolution giving weapons inspectors a stronger mandate.

The House of Representatives was expected to vote in favour of a new resolution on 10 October. The Democrat-controlled Senate has taken a more sceptical view, but appeared ready to fall in line by the end of the week. The proposed text of the resolution stated that: 'The President is authorised to use all means that he determines to be appropriate, including force, in order to enforce United Nations Security Council Resolutions [on Iraq].defend the national security interests of the United States against the threat posed by Iraq and restore peace and security in the region.'

In his 7 October speech, Bush said that Congress approving such a solution 'does not mean that military action is imminent or unavoidable'. He added: 'Congress will.be sending a message to the dictator in Iraq: that his only chance - his only choice is full compliance, and the time remaining for that choice is limited.'

He prefaced his appeal to Congress with a lengthy presentation of the arguments for taking action to disarm Iraq, and the reasons for taking that action now. He sought to establish that there was a real threat to the US from Iraq's arsenal of weapons of mass destruction, even if the evidence of such a threat is still not complete. He invoked the words of President Kennedy to support the case for acting pre-emptively: 'We no longer live in a world where only the actual firing of weapons represents a sufficient challenge to a nation's security, to constitute maximum peril,' Bush quoted Kennedy as saying in October 1962.

Bush's effort to highlight the Iraqi threat was undermined later in the week, when the CIA presented a letter to a Senate committee stating that the probability of Iraq initiating an attack on the US without provocation was very low - although the likelihood of Iraq responding to any US attack with biological or chemical weapons was 'pretty high'.

A large part of Bush's speech was devoted to emphasising that the US was not acting alone. 'Many nations are joining us in insisting that Saddam Hussein's regime be held accountable,' he said. For that to happen, he said Iraq would not only have to get rid of all its weapons of mass destruction, it would also be required to 'end its support for terrorism.cease the persecution of its civilian population.stop all illicit trade outside the oil-for-food programme.[and] release or account for all Gulf war personnel'.

He said that, by taking these steps, Iraq would have the opportunity to avoid conflict. 'Taking these steps would also change the nature of the Iraqi regime itself.' He said he did not expect Iraq to make that choice, and added that this was the reason why both his and the Clinton administration had concluded that regime change in Iraq is necessary.

The Bush speech received a cautious welcome from Egypt's President Mubarak, who said on 9 October that it contained positive elements and that Iraq should respond to it.

Deliberations on a new UN Security Council resolution have continued, amid signs that differences between the US and the UK on one side and France, Russia and China on the other are starting to narrow.