President Bush and senior administration policy-makers have concluded that the United States must not acquiesce in Iraq's invasion of Kuwait and have begun examining options to restore Kuwait's sovereignty and blunt the ambitions of Iraqi President Saddam Hussein, administration officials said yesterday.

Bush sternly warned Iraq yesterday against expanding its invasion of Kuwait into neighboring Saudi Arabia while the administration worked with governments worldwide to cripple Iraq's ability to export its oil.

"The administration can't simply, grudgingly acquiesce" in Iraq's invasion, said an administration official, adding that to do so would create dangerous instability in the region and set a bad precedent for other international disputes. "The level of intimidation will go up if this is permitted to stand," the official said.

The official said Bush has asked policy-makers to come up with a longer-term strategy "to get rid of" Saddam's grip on his tiny neighbor. Officials said that while a timetable for action was unclear, the next move would probably be preparation of a comprehensive package of sanctions in cooperation with U.S. allies in Western Europe and the Middle East aimed at pressuring Saddam to withdraw his troops from Kuwait.

One policy-maker familiar with the internal discussions said the crisis was being viewed as a major challenge to the United States and its allies -- the first of the post-Cold War era of reduced superpower tensions.

After a day of meetings with his senior national security aides, Bush reiterated his call to Saddam to pull his troops out of Kuwait and steer clear of its neighbors in the Gulf.

Noting that the "integrity of Saudi Arabia, its freedom, are very, very important to the United States," he said he would be "inclined to help in any way I can" should that nation be Iraq's next target.

Several members of Congress were far more blunt in warning against moves on Saudi Arabia.

"I think it means war" if that occurs, said Rep. Les Aspin (D-Wis.). House Speaker Thomas S. Foley (D-Wash.) said he would "support concerted military action to support Saudi Arabia."

Rep. William S. Broomfield (R-Mich.), the senior Republican on the House Foreign Affairs Committee, said Saddam "stuck his thumb in our eye. We should break his arm."

Rep. Robert G. Torricelli (D-N.J.) urged the administration to move quickly to bolster Saudi Arabia by placing a wing of U.S. fighter planes on the American-built air bases in that country.

With tensions heightened in the Gulf, the State Department urged Americans in Kuwait to leave as soon as they could and pressed Iraq for information on the 14 missing U.S. citizens believed held by Iraq. The Iraqi ambassador was called to the State Department in an attempt to get information on the missing Americans.

Bush declined to answer whether he has asked Turkish President Turgut Ozal to shut down the pipeline through Turkey that carries Iraqi oil to export markets.

Should both the Turks and Saudis shut down the flow of Iraqi oil, some 90 percent of the country's exports would be stopped.

But Bush said that a shutdown of the oil flow was one option being considered in the international community for what he called "tightening up" the economic embargo of Iraq. "Clearly, a good deal of their oil goes out from . . . Turkey," Bush said, "and that will be an option, I am certain."

The president added, "I think it's fair to say that President Ozal and I look at this matter with the same sense of urgency and concern."

The United States, through the United Nations, is also discussing further multina-tional sanctions, including a blockade of the Gulf, aimed at stopping oil shipped from Iraq or any nation it controls. White House press secretary Marlin Fitzwater, asked what steps were being considered beyond the economic embargo against Iraq imposed on Thursday, cited Chapter VII of the U.N. charter. Fitzwater noted the sanctions chapter lists "the full range of action by air,sea or land forces as may be necessary to maintain or restore international peace or security, including blockades."

The United States informed NATO allies that it did not rule out military action should Iraqi troops go beyond Kuwait, Fitzwater said. The spokesman would not discuss contingency planning for further Iraqi moves but other senior officials said such planning has been going on fullscale since the invasion of Kuwait early Thursday morning.

Bush, heading for Camp David after a day of White House meetings, said that Saudi officials, including Saudi ambassador to the United States Prince Bandar bin Sultan, met with National Security Adviser Brent Scowcroft yesterday, while he had had "a very long" conversation with Saudi King Faud on Thursday.

Bush would not discuss whether the Saudis had asked for further U.S. moves but said, "All you have to do is look at the energy requirements of the world, plus the direct violation of international law by Saddam Hussein to understand why I feel so strongly about" threats against Saudi Arabia.

"I want to make very clear to everybody how strongly I feel about the nature of this uncalled for invasion and our determination to see the matter resolved," Bush told reporters on the South Lawn of the White House.

Bush and other administration officials reacted with some skepticism over reports from Iraq that their troops would begin to be withdrawn from Kuwait by Sunday. The president said, "Let's see them haul them out right now." Other officials said there was no evidence on the ground of such a move and reiterated their statements that Saddam has lied to U.S. officials repeatedly about his intentions.

Fitzwater said at midday that Iraq's response to the international pressure to withdraw had been "only scorn." He said at day's end that he had no reason to change that assessment but added that the United States was hopeful that stronger condemnation from Middle East countries and threats of broader sanctions would produce some movement by Iraq.

Part of Bush's discussions yesterday centered on the potential impact on U.S. oil supplies by the sanctions already imposed. Fitzwater downplayed that impact, noting that the immediate affect would be "moderate or slight." But Bush acknowledged that a long interruption in the oil supply to the United States and rest of the West was a major concern. "Long-run, economic effects on the free world could be devastating," the president said, "and that's one of the reasons I am as concerned as I am."

Bush was expected last night to call a list of other foreign leaders in his effort to press a broad, international response to the invasion. The French prime minister was among those Bush planned to talk with. Earlier in the day, he consulted with British Prime Minister Margaret Thatcher. A group of key advisers is scheduled to go to Camp David today to meet with the president on the gulf crisis.