President Bush gave congressional leaders little hope yesterday that war in the Persian Gulf can be averted as the White House held to its public stance that military action will not be delayed much past Wednesday if Iraqi forces remain in Kuwait.

Bush spent his day in a series of conversations with international leaders and in White House sessions devoted to the crisis. His spokesman, Marlin Fitzwater, warned that military action "could occur at any point" past midnight (EST) tonight, the deadline set by the United Nations for Iraq to withdraw from Kuwait. "Any moment after the 15th is borrowed time," he said.

Fitzwater said that despite a last-minute "flurry" of diplomatic efforts at producing a solution, the administration saw little reason for optimism. He cited the report to Bush by United Nations Secretary General Javier Perez de Cuellar describing Iraqi President Saddam Hussein's continued intransigence and and noted, "His {Saddam's} response to the secretary general, his response to all those who have talked to him in recent days, has been hard-line, showing no flexibility and no indication that he intends to leave Kuwait."

The White House last week began emphasizing privately that Bush is disposed to move quickly after the deadline, and Secretary of State James A. Baker III, followed by a string of other administration spokesman, picked up that theme last weekend as Jan. 15th neared.

A senior official said the administration's current assessment is that Saddam is counting on enough time passing between the deadline's expiration and the beginning of any military action to win Arab approval for having faced down the U.S. deadline and still be able to begin pulling his forces out of Kuwait and complicate any military strike.

"I think if he is playing chicken, he will hope that he can get away with the deadline passing and he can claim he stood down the world, and he'll hope to have enough warning" that he can back down later, the official said. Today, the official said, "is a watershed date beyond which he can say he is a hero," an outcome Bush wants to avoid, the official said.

Another sign of the state of relations between the United States and Iraq was the announcement by Iraq's ambassador here, Mohamed Mashat, who had become a prominent spokesman for his government to the American media, that he will leave Washington before the deadline expires. The State Department also announced that Iraq's 18 diplomats and staff at the United Nations in New York would not be allowed to travel beyond New York City.

The latest Washington Post-ABC News Poll found strong support for use of military force after tonight's deadline expires. It indicated that two out of three Americans continue to approve of the way Bush is handling the crisis and nearly four of 10 favor immediate military action after midnight, with nearly seven out of 10 saying they would support military action at some point.

At the meeting with congressional leaders, Baker, just returned from an eight-day trip consulting with world leaders, gave a more detailed account of his meeting in Geneva last week with Iraqi Foreign Minister Tariq Aziz. "There was nothing encouraging to report," said House Minority Leader Robert H. Michel (R-Ill.).

Defense Secretary Richard B. Cheney said the costs of Operation Desert Shield over and above regular Pentagon spending were about $10 billion from August through Dec. 31, according to Michel. In addition, Cheney said the United States now had well over 400,000 troops in the gulf, bolstered by the arrival in the last few days of three more aircraft carrier battle groups, according to Michel.

After meeting with Canadian Prime Minister Brian Mulroney in Ottawa yesterday morning, Baker said prospects for a peaceful settlement are "deteriorating."

Reacting to Perez de Cuellar's failed mission, Baker said, "It seems to me that this is one more rejection by Saddam Hussein of a peace envoy to Baghdad. It is one more indication of Saddam Hussein's callous disregard of the well-being of the Iraqi people."

On his way back to Washington, Baker also spoke by telephone with Jacques Poos, foreign minister of Luxembourg and head of the European Community, who told Baker that Perez de Cuellar's mission had been "very discouraging" and that the EC planned no further overtures to Baghdad.

The State Department also disclosed that Baker had spoken by telephone on the trip to Yemen's foreign minister, Abdel-Karim Iryani, while he was visiting Egyptian President Hosni Mubarak on Saturday. Yemen indicated it was trying to put together a new diplomatic initiative, according to the State Department official, but the United States saw nothing new in it and Fitzwater repeated that assessment yesterday.

Assistant Secretary of State John H. Kelly visited the foreign minister for a half-hour in his hotel in Cairo, the official said.

The events of the last several days have persuaded an increasingly large number of Americans that the United States will eventually go to war. Nine of 10 Americans surveyed now hold that view, but more than half -- 57 percent -- of those polled still want the administration to seek diplomatic talks with Saddam. And two out of three respondents also said the United States should agree to an international peace conference on the Middle East if Iraq agreed to withdraw from Kuwait.

The Bush administration opposes such a conference, wishing to avoid any link between the Persian Gulf crisis and the Arab-Israeli issue.

While Americans strongly support Bush, 50 percent of those interviewed disapproved of the way Congress has handled the crisis while 47 percent approved.

Three out of four persons questioned said they approved of Congress voting to allow Bush to go to war. And 44 percent said Congress acted too late while 46 percent said lawmakers voted "about when they should have."

A total of 781 randomly selected adults were interviewed for this survey. Margin of sampling error for a sample of this size is plus or minus 4 percentage points.

While most Americans appear willing to accept a war with Iraq, the latest Post-ABC poll shows that just over a third -- 37 percent -- of those interviewed said the United States and its allies should begin military action immediately when the deadline expires. That is up from 27 percent in a Post-ABC poll last week.

Another 21 percent would support beginning hostilities within a month. Nearly two out of three persons questioned said they would accept war within three months if Iraq has not withdrawn from Kuwait.

Staff writers Dan Balz, David Hoffman, John E. Yang, Richard Morin and Al Kamen contributed to this report.