The Bush administration said yesterday it was within close range of majority support for a new U.N. resolution authorizing war with Iraq, but no other country stepped forward to say it had decided to vote for the measure.

Despite administration confidence, expressed in White House and State Department briefings for reporters, at least two of the six Security Council members whose agreement is being sought -- Chile and Mexico -- had yet to be persuaded to vote in favor of the resolution, sources close to the discussions said.

The United States has insisted on a vote by Friday, and if both Latin American countries oppose it, the resolution will fail to obtain the necessary nine of 15 council votes to pass. Five council members, including France and Russia, have said publicly they will not support what they see as an unjustified rush to war, while only four -- the United States, Britain, Spain and Bulgaria -- are publicly behind it.

"There is widespread agreement," said a diplomat from one of the six countries, which consist of three African nations and Pakistan in addition to the Latin American countries. But it is "against authorizing the use of force," rather than the approval implied yesterday by the administration. "This is going nowhere," another diplomat said. Seeking to stave off outright rejection, Britain asked council ambassadors in a closed meeting last night to take another 24 hours to consult with their governments about changes it has proposed to the resolution.

President Bush has said he will make his final decision on Iraq with or without U.N. approval, and White House officials were making preparations for a presidential address to the nation shortly after U.N. deliberations end. Administration officials said they expect Bush to issue a disarmament ultimatum to Iraqi President Saddam Hussein, including a date after which military action could occur. That would serve as a signal for journalists, humanitarian workers and others to leave Iraq if they chose to.

As the administration moves quickly toward concluding its war preparations, Bush met again yesterday with his top national security officials, including Defense Secretary Donald H. Rumsfeld, Secretary of State Colin L. Powell, and Air Force Gen. Richard B. Myers, chairman of the Joint Chiefs of Staff.

Bush said during his news conference last week that he wanted council members to "show their cards" in a vote, no matter what the outcome. Although a veto by any of the five permanent council members, including resolution opponents France, China and Russia, would doom it to immediate failure, senior U.S. and British officials have said they would consider even a vetoed nine-vote majority enough to justify war.

But the prospect of near-certain defeat is causing extreme anxiety in London and Madrid, where the failure to cobble together even a majority of supporters would imply political isolation on the eve of a war. There was rising speculation in both capitals that the resolution might be withdrawn before a vote. Spanish Foreign Minister Ana Palacio suggested that was "a possibility" in the face of "absolute and categorical affirmation of France to veto," although a foreign ministry spokesman later clarified her remarks as a "hypothetical" statement of "a very distant possibility."

Britain has committed tens of thousands of troops to the military buildup in the Persian Gulf region that is dominated by U.S. forces numbering more than 200,000. But it appeared increasingly frantic yesterday to fashion resolution wording acceptable to at least five of the undecided members, while still meeting stringent U.S. requirements.

British diplomats at the United Nations for the second time proposed changes in the resolution they first offered late last month with the co-sponsorship of the United States and Spain. Responding to concerns raised by the six countries whose agreement is being sought, the British added a "side statement" of specific disarmament tests for Iraq to pass by the March 17 deadline insisted on by Washington, including a television appearance in which Hussein would admit he had concealed weapons of mass destruction and was prepared to turn them over to U.N. inspectors.

The benchmarks would also require Iraq to allow at least 30 scientists and their families, selected by inspectors, to travel outside the country for interviews on Iraqi weapons programs; to surrender all remaining stores of anthrax bacteria along with all information on chemical and biological weapons programs; to destroy all Al Samoud-2 missiles, components and production facilities; to account for all unmanned aerial and remotely piloted vehicles; and to surrender all mobile production facilities for biological and chemical weapons. The British indicated in discussions with the six that the March 17 deadline for Iraqi compliance could be extended.

But British negotiators were hampered by the refusal of the United States to publicly commit itself to any of the changes they were trying to sell, leaving a number of council members frustrated and confused about whether they were being asked to sign off on something the United States had not agreed to.

Referring repeatedly to the "British ideas" and "British proposals," State Department spokesman Richard Boucher said their usefulness would depend on how successful they were "in terms of getting other members of the council on board." In his only comment on the specifics of the proposals, White House spokesman Ari Fleischer said there was some U.S. "flexibility" in the March 17 deadline, but senior officials have said it extends only to about a week after the council vote.

Boucher said yesterday that the resolution proponents were "making progress" in winning votes, "but I don't want to mislead you into thinking that we've got it in the bag." U.S. and British officials privately implied that Pakistan and the three African nations, Guinea, Angola and Cameroon, would support the measure. But none of those countries confirmed a decision.

All of the six have said they believe U.N. weapons inspections should be given more time. In consultations with British diplomats yesterday, sources said they raised questions about whether the suggested benchmarks met with the approval of chief inspector Hans Blix, and insisted that the deadline was far too short.

In Mexico, where President Vicente Fox underwent back surgery yesterday and was expected to be hospitalized until Friday, sources familiar with government deliberations said Mexico remained opposed to the resolution. In Chile, President Ricardo Lagos said he was "optimistic a couple of days ago, but now I believe . . . [only] a miracle would help us advance. But I see that as very unlikely."

Committed opponents criticized the British initiative, saying it was a barely veiled authorization of military action. Gunter Pleuger, Germany's U.N. ambassador, said the British benchmarks were designed to ensure that Iraq could never fulfill them, according to a council diplomat. Russian Ambassador Sergey Lavrov complained that his delegation had not been given sufficient time to study the British text and urged the council to allow Blix to determine the remaining tasks for Iraq and allow 120 days before meeting to assess Baghdad's cooperation.

Several delegates expressed exasperation at the intense pressure that was being brought to bear to secure their votes. "We still hope this movement, this diplomatic game in the Security Council, might give the international community a hope of peace," said Munir Akram, Pakistan's ambassador to the United Nations. "We still hope Bush might listen to the huge international reaction" against war.

Bush called Pakistani President Pervez Musharraf and Russian President Vladimir Putin yesterday, but there were no reports of progress. Alexander Vershbow, the U.S. ambassador to Moscow, said in an interview published in the newspaper Izvestia that billions of dollars of Russian oil contracts in Iraq were at stake.

Russia's role in the economic restructuring of postwar Iraq, Vershbow said, "will depend on how the situation develops in the next few days."

Staff writer Mike Allen in Washington and correspondents Sharon LaFraniere in Moscow and Kevin Sullivan in Mexico City contributed to this report. Lynch reported from the United Nations.