Updated

Exactly six months after President Bush's dramatic appearance at the United Nations to galvanize action on Iraq, the United States and others were searching for a way out of an impasse created by Washington's demand that Baghdad be given an ultimatum.

The ultimatum was contained in a proposed resolution that would authorize war after March 17 unless Iraq disarmed. As it was going through revision, it became clear that Washington and London — the resolution's co-sponsor — still didn't have enough support for the initiative.

Britain — which needs the resolution at a time when Prime Minister Tony Blair is looking politically vulnerable at home — took the lead Tuesday along with Canada in trying to break a stalemate over how much time Saddam Hussein should be given to prove he has disposed of his most dangerous weapons.

France, Russia and China — all with veto power — oppose the U.S.-backed resolution, with Paris threatening to veto any measure that contains an ultimatum or the automatic use of force.

Six countries that hold the key to a U.S. victory in the Security Council proposed a 45-day reprieve for Iraq. U.S. officials said they were willing to listen to the informal proposal but envisioned a far shorter deadline of seven to 10 days from the resolution's passage.

White House spokesman Ari Fleischer said the United States would put a text to a vote some time this week. But another senior administration official said on condition of anonymity that State Department officials were trying to persuade the White House it might be better to postpone the vote and avert a veto.

By late Tuesday, it appeared that a carefully worded compromise could get the United States the nine necessary "yes" votes it needs to have a majority in the council. Senior diplomats said that despite rhetoric from Islamabad, Pakistan appeared to now be on board with the United States.

That gives the United States the support of Britain, Spain, Bulgaria, Pakistan, Cameroon and Mexico, meaning it only needs two of the other three undecideds — Guinea, Angola and Chile.

Syria and Germany were expected to oppose the resolution or abstain along with France, Russia and China.

On Sept. 12 of last year Bush came to the United Nations and delivered a challenge to the world body to get tough with a derelict Iraq or stand aside as the United States acts alone.

It was a challenge the Security Council — and Iraq — seemingly took seriously. Saddam announced four days later that inspectors were welcome to return to his country after a four-year absence. And the council plunged into eight weeks of intensive negotiations which produced Resolution 1441 — a toughly worded guide for inspectors and a warning to Saddam that he had a final opportunity to disarm or face "serious consequences."

The United States and Britain believe the Iraqi leader failed to use the chance to disarm and cooperate with inspections.

Bush and Blair have both said they would disarm Iraq, if necessary, with a coalition of allies if the U.N. refuses to pass the resolution. But U.N. backing would give a war international legitimacy and ensure that the costs of reconstruction would be shared by the organization.

As America kept its war plans on hold, with hundreds of thousands of troops waiting for orders to strike, diplomats grappled over the details of how Iraq might avoid bloodshed.

The British were talking about a giving Iraq 10 days to prove it has made a "strategic decision" to disarm. It would then have a brief window to carry out a series of disarmament tasks that would be verified by inspectors. Should it fail to complete the tasks, then a coalition of willing nations would have a free hand to strike.

The Canadian proposal, strongly backed by Chile, a key swing vote on the council, would set a three-week deadline for Iraq to show it is cooperating fully with a set of disarmament tasks drawn up by the weapons inspectors, rather than by London and Washington. A close aide to Chilean President Richardo Lagos called it a "checklist of about 12 items."

If Baghdad is found to be cooperating, new deadlines could be set until all the disarmament goals are met.

The Canadian plan was aimed at finding a compromise among the needs of the British, U.S. insistence that any resolution authorize force if necessary, and the concerns of a handful of council members wary of a rush to war. While diplomats conceded that it still didn't address the fundamentals France has championed, it may be enough to persuade Paris to abstain in a vote rather than veto.

Facing revolt within his own Labor Party, Blair is under intense pressure at home to get U.N. backing for any fresh military action.

"The United Kingdom will only act within international law and we're looking for the United Nations to remain in control of this huge issue," British Ambassador Jeremy Greenstock said Tuesday. "We're going to go on talking until we find a way forward for the Security Council together."