Climax Nears in Showdown With Baghdad : Arms: U.N. awaits Iraq’s response to proposed compromise over access for weapons inspection team.

The confrontation between the United Nations and Iraq moved further toward a climax, possibly this weekend, as the Security Council on Friday awaited Baghdad’s response to a proposed compromise over Iraq’s refusal to let U.N. weapons inspectors enter its Agriculture Ministry building.

After a day of more diplomatic churning by all sides, Iraq’s U.N. ambassador, Abdul Amir Anbari, told reporters that he expected to get his government’s answer today, and was optimistic that “the crisis will be resolved in a very constructive way.” He is scheduled to meet with U.N. officials this morning.

Meanwhile, President Bush, campaigning Friday in Ohio and Missouri, canceled plans for a brief vacation in Maine and returned to his Camp David, Md., retreat to huddle with his national security advisers to map his next step if the proposed compromise falls through.

White House Press Secretary Marlin Fitzwater, lashing out at what he called Iraq’s “across-the-board defiance,” called the showdown with Baghdad “probably the most serious that we’ve faced” since the end of the Gulf War in March, 1991.

Fitzwater also confirmed that the United States, France and Britain are considering issuing an ultimatum to Iraq as the last step before launching a military strike. He described the issue as “still open and under discussion,” but he insisted that no decision has been made yet.

“There’s no timetable at this point, but obviously as you consider the matter, there has to be some point at which final judgments are made,” Fitzwater said. But he told reporters earlier that the situation was “edging up on” a deadline.

It was not immediately clear whether Iraq’s response to the U.N. proposal would satisfy the United States and other Western allies, particularly if Baghdad tries to alter the terms. U.N. officials said Friday that they shared Anbari’s optimism, but they declined to disclose details of the plan.

Some reports suggested that the crux of the U.N. proposal was to eliminate all Americans from the U.N. weapons inspection team, which currently is dominated by U.S. nationals, in return for which Baghdad would guarantee the safety of the new team members. But officials here cautioned against such speculation.

There was no indication just how quickly the White House might choose to issue an ultimatum if Iraq chooses not to back down. The United States, Britain and France already have made clear that they will set any such deadline jointly and coordinate any military action.

An Administration official said that there was no longer any disagreement within the Cabinet about resorting to military action should it become necessary, and that if an ultimatum is issued, a military strike will follow relatively quickly.

“Everyone’s on board here,” the official said. “No one has any reservations.”

Still, despite the tough-sounding rhetoric from the White House, the Administration sought to stress simultaneously that the United States and its allies were not about to rush into any military action without allowing time for Iraq’s response.

In Washington, a key Administration official cautioned that this morning’s session between Bush and his advisers would not necessarily lead to an immediate ultimatum. He said Bush had merely asked for “a clear view of what the ramifications of a military operation would be.”

“Everyone wants to make sure they’ve got everything lined up just right,” the official said. “I don’t think this is going to be the final nod for a military operation.”

Officials said Bush would be presented with a variety of options for military action but that the outcome would depend mainly on Iraq’s response to the U.N. proposal. They also cautioned that the need to consult with Washington’s allies could delay any deadline-setting until early next week.

Friday’s developments came after Rolf Ekeus, the official who heads the U.N. inspection effort, announced that five more of the U.N. weapons inspectors who have been barred from the Iraqi Agriculture Ministry--believed to hold records of Iraq’s missile program--for the past 19 days left Baghdad for Bahrain after repeated intimidation.

Ekeus said two of the original team members will remain in the Iraqi capital, along with about 65 other U.N. inspectors and support personnel who have been involved in enforcing the cease-fire agreements. Seven other members of the inspection team left earlier this week.

The atmosphere at the United Nations was tense Friday as all sides awaited the Iraqi response. Ambassadors of the United States and its major allies met briefly with U.N. Secretary General Boutros Boutros-Ghali but apparently reached no decisions. Ekeus and Anbari will meet this morning.

Meanwhile, the Navy announced that a U.S. amphibious battle group arrived in the Persian Gulf on Friday to join other American warships in joint exercises with warships from several countries, bringing to 24 the number of U.S. vessels now stationed in the area.

It was not immediately clear how large a force might be assembled or which Iraqi sites would be targeted if the shooting began. The Americans, British and French would be expected to provide the bulk of the firepower, possibly using aircraft based in Saudi Arabia as well as carrier-launched planes.

U.S. officials have insisted repeatedly that Bush would not order American ground troops into action but would confine U.S. participation to air and naval forces.

White House officials said the rare weekend session with the President, expected to last about two hours, will include National Security Adviser Brent Scowcroft; Defense Secretary Dick Cheney; Gen. Colin L. Powell, chairman of the Joint Chiefs of Staff, and other top advisers.

Administration officials said the President’s decision to adopt a hard line on Iraq had been made somewhat easier by the statement by Democratic presidential candidate Bill Clinton earlier this week that he would support any U.N.-backed response.

They said the Administration also had felt more comfortable about hardening its stance after Saudi Arabian officials voiced support for military intervention in meetings with Secretary of State James A. Baker III during his recent Mideast tour. Baker warned on Friday that a strike was “almost certain” unless Iraq backs down.

Bush’s action in abruptly canceling the weekend trip to his vacation home in Kennebunkport, Me., was clearly intended to send as strong a signal as possible to Hussein.

Administration officials believe that Hussein has become emboldened by the fact that Bush is engaged in a tough reelection fight, and they say they intend to “disabuse” the Iraqi leader of his apparent optimism that the campaign would constrain any U.S. response to his defiance.

The issue also carries domestic political ramifications. Bush’s announcement earlier this week that he would head to Maine for the weekend drew a sharp reaction around the country amid criticism that the President appears to be spending too much time playing golf and boating.

Bush did not directly address the crisis during his campaign stops Friday. But as he had in a morning address in Washington to the families of Americans missing in Southeast Asia since the Vietnam War, he devoted unusual attention to his role as commander in chief during the Gulf War.

He reminded the audience that before U.S. forces drove the Iraqi army from Kuwait, he had vowed that “aggression will not stand.”

Pine reported from the United Nations and Jehl from Washington.