With a quarter-million troops readied for an attack on Iraq, the United States and Great Britain pushed their U.N. proposal to give Saddam Hussein until March 17 to comply with disarmament demands — or face war.

The ultimatum, in the form of a U.S.-backed resolution, was designed to attract support from a handful of undecided members of the U.N. Security Council. It met a flat rejection from France, Russia and China, and on Saturday both sides were campaigning for votes.

With U.S. officials saying they want a vote as soon as Tuesday, British Foreign Minister Jack Straw — whose country joined the United States and Spain in proposing the deadline at a highly charged council session Friday — insisted the measure could still be passed despite opposition from three veto-holding members.

"We are at a difficult time, but I believe that by the process of argument we should be able to get to a point where we can get a second resolution," Straw told British Broadcasting Corp. radio on Saturday. Prime Minister Tony Blair was in close contact with world leaders in a bid to build support, Blair's office said.

The document states that war will be necessary if Iraq fails to take the "final opportunity afforded by Resolution 1441" on or before March 17, "and the council concludes that Iraq has demonstrated full, unconditional, immediate and active cooperation with its disarmament obligations."

"There was a hesitancy by countries to vote for anything that automatically goes to war," one U.S. official told Fox News.

International Response to Iraq Ultimatum

Russian Foreign Minister Igor Ivanov said his country opposes settling a deadline and warned that unilateral military action against Iraq would violate the United Nations' charter.

"If the United States unilaterally begins military action in relation to Iraq, it would violate the U.N. charter and, of course, when the U.N. Charter is violated, the Security Council must gather, discuss the situation and make the corresponding decisions," Ivanov said in an interview with Russian television released Saturday.

The proposal has already received harsh criticism from France, which has been the leading opponent of war and has advocated more stringent inspections.

France rejected the deadline proposal and threatened to use its veto to defeat it.

"This is the logic of war — we don't accept this logic," French Foreign Minister France de Villepin told reporters. "We cannot accept an ultimatum as long as inspectors are reporting cooperation," he told the council earlier. "France will not allow a resolution to pass that authorizes the automatic use of force."

De Villepin suggested instead another Security Council meeting, this time attended by heads of state who would decide the course of war and peace. Secretary of State Colin Powell dismissed the idea.

Nevertheless, French President President Jacques Chirac was lobbying other heads of state to join him at an emergency summit, his office said Saturday. De Villepin was to leave Sunday evening for Angola, Cameroon and Guinea — key swing votes on the Security Council — to seek their leaders' support.

Key fence-sitting countries such as Angola, Pakistan and Chile said Friday that they had problems with the resolution. Asked whether Angola could accept the new text, Angola's ambassador, Ismael Gasper Martins, said, "Unfortunately not."

"I don't think it's the sort of compromise that we were looking for or that we can support, not yet," he said.

The United States needs to be open to negotiations, he said, if it wants to gain support before a vote next week.

German Foreign Minister Joschka Fischer said the short ultimatum "will lead in a very short period to military action."

U.S. Lobbies Allies for Support

President Bush, Powell and National Security Adviser Condoleezza Rice planned to lobby allies by telephone until the vote.

"It is clear that Saddam Hussein is still violating the demands of the United Nations by refusing to disarm," Bush said Saturday in his weekly radio address.

If we need to act, "we will act, and we do not need the United Nations' permission to do so," Bush said.

Washington hasn't yet gained the nine votes necessary for the resolution's passage. Six nations out of the 15 Security Council members are publicly undecided.

The deadline was a disappointment also for Chile and Angola — two other council members whose support the United States needs.

Only Bulgaria plus Spain and Britain — which co-sponsored the U.S. resolution — have committed to supporting the deadline.

The U.S. and Britain also quietly disagree over whether Saddam will be allowed to remain in power if Iraq complies. Britain sees no need for a regime change if Baghdad disarms, but the United States wants the dictator permanently removed from power.

Inspections Continue in Iraq

Iraq's Ambassador Mohammed Al-Douri said the inspectors haven't yet proven that Baghdad has weapons of mass destruction.

"The U.S. administration and Britain continue to attempt to trump up facts and evidence pointing to Iraq's possession of weapons of mass destruction. However, they have come short of convincing the international community," he said.

The political wrangling over the resolutions continued even after chief weapons inspectors Hans Blix and Mohamed ElBaradei told the Security Council Friday that although Iraq has carried out a "substantial measure" of U.N. demands — albeit slowly — there is still more work to be done.

Blix said Iraq's destruction of its Al Samoud 2 missiles constitutes a "substantial measure of disarmament."

"We are not watching the breaking of toothpicks — lethal weapons are being destroyed," he said.

Blix said weapons inspectors will interview scientists outside Iraq for the first time, since "conditions ensuring the absence of undue influences are difficult to attain inside Iraq."

While it's "obvious" that Iraq is making attempts to resolve disarmament issues, Blix stressed, "these cannot be said to constitute immediate cooperation."

ElBaradei said nuclear inspectors will continue, but he said: "We have to date found no evidence ... of the revival of a nuclear weapon program in Iraq."

U.S., Allies Skeptical of Iraq's Cooperation

The reports were met with staunch repute from the United States, Britain and Spain.

Secretary of State Colin Powell called the reports — plus an additional 167-page report detailing the 12-year history of Iraq's noncompliance — a "catalog of noncooperation" by Saddam.

"Iraq's small steps certainly are not initiatives," Powell said. "They have been pulled out or have been pressed out by the possibility of force by the political will of the Security Council … only grudgingly, rarely unconditionally and primarily under the threat of force....

"The clock continues to tick and the consequences of Saddam Hussein's continued refusal to disarm will be very real," Powell warned.

Fox News' Teri Schultz and Jim Angle and The Associated Press contributed to this report.