The American people should steel themselves for a Persian Gulf War that probably will last months and include Iraqi victories, the White House said yesterday in a campaign to dampen lingering expectations of a quick or bloodless end to the conflict.

"There are going to be ups and downs, there are going to be enemy victories, there are going to be enemy surprises, there are going to be days when we'll see allied losses, and . . . we need to get into a frame of mind that allows us to accept those reverses and surges," White House press secretary Marlin Fitzwater said.

President Bush and Defense Secretary Richard B. Cheney echoed that theme in a White House meeting with congressional Republicans, expressing concern that the U.S. public may have unrealistically expected allied forces to drive Iraqi troops out of Kuwait in a few days. "We need to get on kind of an even keel in terms of our public psyche," Fitzwater said following the session.

Lawmakers picked up the White House theme, saying they now recognized that the war is not likely to end quickly and warning that a protracted conflict could jeopardize domestic spending programs and the anticipated peace dividend. "It's not going to be a short war," House Minority Leader Robert H. Michel (R-Ill.) said.

Yesterday's White House comments were the latest reiteration of a cautionary note that Bush first struck in a speech less than two days after the war began last week. The president's caution was intended to suppress public euphoria spawned by the allies' low casualties and technological superiority against an enemy that absorbed the war's early blows without much of a fight.

On Monday, Cheney became the first senior administration official to say publicly that the war could conceivably last for months, and Fitzwater echoed that view in his daily briefing. "We've said probably months," he stated. Yesterday's message also reflected recent U.S. government assessments that the Iraqi military could successfully drag out the war far longer than most Americans had hoped.

The day also brought an outbreak of partisan sniping in Washington, with Republicans threatening to make a campaign issue out of Democratic resistance to a congressional resolution passed two weeks ago giving Bush the authority to wage war. The controversy was sparked by comments made this week by newly designated Republican National Committee Chairman Clayton Yeutter, who was quickly rebutted by House Speaker Thomas S. Foley (D-Wash.)

U.S. troops continued to pour into Saudi Arabia in preparation for what many commanders -- and U.S. officials -- believe is an increasingly inevitable ground war after a month or so of air attacks. The United States will deploy more than 500,000 military personnel in Operation Desert Storm, a number approaching the maximum troop strength in Vietnam, U.S. officials predicted yesterday. Despite the buildup and expectations of a months-long war, military officials do not expect any shortage of critical missiles or bombs.

The eighth day of war saw some of the most intense air activity to date -- more than 2,000 sorties, half of them bombing runs -- and other action including a small naval battle, a dogfight and a U.S. Marine rehearsal for what was described as potentially the largest amphibious landing since Inchon in Korea more than 40 years ago.

In the air war, clear skies south and east of Baghdad permitted "a highly successful period of operations" against Iraqi Republican Guard units, command and communication facilities and transportation targets, a U.S. Army spokesman in Riyadh said. French jets for the first time attacked targets in Iraq, striking Guard positions north of the Kuwaiti border, while other allied forces destroyed three Iraqi Badger bombers sitting on the ground at an airfield.

U.S. officials again released very little information regarding the destruction -- or survival -- of enemy targets. "We're still trying to figure it out," an Army spokesman in Riyadh said. An Iranian news agency reported continuing attacks by warplanes and sea-launched missiles against the Iraqi city of Basra between Baghdad and Kuwait, a key stronghold in the allied strategy of strangling Iraq's army of occupation. Two Iraqi Planes Downed

A Saudi jet shot down two of Iraq's best warplanes over Saudi coastal waters, reportedly foiling the first known attempt by Iraq to bomb allied targets. Allied forces captured 51 Iraqis after attacking two minelayers in the Persian Gulf off the coast of Kuwait.

As a helicopter from a U.S. warship was plucking 22 Iraqi prisoners from the sea, other enemy forces fired from the tiny nearby island of Qurah. Counterattacking allies killed three Iraqis and captured another 29, Lacombe said.

Reported allied losses yesterday included a U.S. Air Force F-16 hit above Kuwait. Another British Tornado -- the sixth since the war began -- was also lost.

Other than minor border skirmishing and brief artillery duels, the only other significant action reported involved thousands of Marines "conducting an amphibious rehearsal in the Arabian Gulf" for a possible assault on Kuwait in the future. Much of the allied ground maneuvering now is believed to involve feints intended to deceive and confuse Iraqi forces.

Noting that U.S. officials increasingly have predicted a protracted conflict, Baghdad Radio yesterday said the combat is following a course "contemplated by Iraq, which wanted the war to be a long one." Allied forces will be struck "in the same manner we strike stray camels," an Iraqi broadcast warned.

President Saddam Hussein risked allied bombs to visit his southern front yesterday, Baghdad Radio and the official Iraqi News Agency reported. Without specifying whether Saddam was in Kuwait or southern Iraq, the accounts said Saddam had conferred with his commanders, who reportedly mocked the allies for avoiding a ground war "because of cowardice and fear of combat." Saddam exhorted his forces to resist, saying the battle would be decided by Iraq's superior "willpower and patience."

Another message, delivered in the name of the General Command of Iraq's Armed Forces and labeled "communique number 19," said Iraqi forces shot down another "three enemy air targets," bringing to 172 the number of allied planes and cruise missiles claimed. The official Iraqi News Agency yesterday also said 90 Iraqi soldiers were killed in the first six days of war.

Although providing few details of the bomb damage, the Iraqi media this week has focused on alleged civilian casualties in an apparent effort to inflame the population. "One of Bush's claims is that he will fight the Iraqi forces," one broadcast declared, "but we find him targeting civilian citizens -- women and children."

Iraqi authorities provided videotaped footage to Cable News Network, the only known Western news organization still in Baghdad, purportedly showing smashed houses and other damage in the northern city of Mosul. In a broadcast reviewed by Baghdad, the network also reported damage to several suburban areas in the Iraqi capital, including damage to businesses, a psychiatric hospital and a mosque.

Administration officials continued to insist that Saddam has not been personally targeted for allied bombing, but indicated that if he survives the war, he still may face punishment of some sort.

A senior official said the United States has been "keeping track since Aug. 2," when Iraq invaded Kuwait, of Saddam's violations of international law. The official said these violations have included Iraqi treatment of hostages, diplomats and now prisoners of war. "You may have forgotten, but we have not," the official said.

The allies have several potential ways of dealing with Saddam after the war, the official added, including demands for compensation through the United Nations or a decision to maintain sanctions against Iraq "until he is turned over" by a new government there.

Meanwhile, Rep. Lee H. Hamilton (D-Ind.), a leading opposition foreign policy spokesman, said Bush has made the U.S. challenge in the Middle East "more difficult" by expanding allied war aims. "It is not clear to me what winning this war means," Hamilton said in a National Press Club speech. "The president has stated limited objectives" centered on complete and unconditional withdrawal from Kuwait and full compliance with 12 U.N. Security Council resolutions.

"But his recent statements and our military actions suggest that our goals are expanding to include the surrender of Iraq and the destruction of its military," he added. "To the extent that we expand our objectives, it will make more difficult the diplomatic task when the fighting stops."U.N. Initiatives Stopped

Diplomatic efforts to bring at least a pause in the bombing if not a cease-fire failed again yesterday. A group of Arab nations could not muster the necessary support to call a meeting of the U.N. Security Council. The current Council president, Bagbeni Adeito Nzengeya of Zaire, said a majority of the members believe no further action should be taken until Iraq complies with all previous U.N. resolutions.

The action appeared to doom efforts by several North African countries as well as a separate effort by Yemen, whose president, Ali Abdallah Salih, accused the United States yesterday of attempting to destroy Iraq rather than liberate Kuwait. "The target is not only Iraq but the whole Arab and Islamic nation," Salih told a news conference in Yemen.

Sniping among allied nations broke out yesterday, as Turkish President Turgut Ozal lashed out at Germany for providing Iraq with much of its chemical weapons capability and what he said was Germany's unwillingness to protect the Turks now that the war has begun. "I think Germany has become so rich that it has completely lost its fighting spirit," Ozal said in an interview with a German television network.

Ozal has emerged as one of the Bush administration's favorite allies in the gulf war, with one official describing him yesterday as "a lion" who has "shown great courage." Another administration official said the United States is working hard to keep Turkey's leadership calm in the face of domestic protests over Ozal's decision to allow U.S. planes to launch air strikes against Iraq from bases in his country. "We're way past the hand-holding stage," the official said.

Bush met yesterday with special envoy Richard Armitage, who just returned from a visit to Jordan, where he conveyed to King Hussein U.S. displeasure with continuing statements from the Jordanian monarch that tilt toward Iraq and that have threatened Israel with force if the Israelis use Jordanian air space to respond to Iraqi Scud missile attacks. One official said the Jordanian leader complained that the United States has failed to understand the problems of a country "in the middle."

The continuing unrest in the Arab world only served to underscore warnings of possible terrorist attacks. In the Philippines, for example, a bungled anti-American bombing by two Iraqis last week has prompted a scramble among intelligence agencies there to unravel what they suspect is a vast Iraqi-sponsored terror network in Asia.

FBI Director William S. Sessions, however, said that while the bureau had identified elements of international terrorist organizations in the United States, "I think we ought to go about our business as usual." The director urged football fans heading for this week's Super Bowl in Tampa, Fla., "to go and enjoy it."

Assistant FBI Director William M. Baker, head of the bureau's criminal investigation division, cited the Abu Nidal organization as the primary threat. Other groups, including Hezbollah, the Palestine Liberation Organization and the Democratic Front for the Liberation of Palestine, also have presences in this country. Terrorist attacks, Baker added, might come from "individual zealots."

On Capitol Hill, Sen. Joseph R. Biden Jr. (D-Del.), chairman of the Senate Judiciary Committee, proposed legislation to fill what he said were "several gaps in our current anti-terrorism laws." The measure would make a wide range of terrorist acts federal crimes, from financing of terrorist groups to murders intended to force U.S. withdrawal from the gulf. Biden's bill also would provide the death penalty for terror acts of murder committed in this country or against U.S. citizens abroad.

Yesterday's White House statements urging Americans to brace themselves for a protracted conflict also echoed statements by Cheney and Gen. Colin L. Powell, chairman of the Joint Chiefs of Staff, in a briefing Wednesday. In outlining the allied strategy for isolating and then "killing" the Iraqi army in Kuwait, Powell said the process would take time in order to batter Iraqi forces from the air before risking the lives of allied ground forces.

Delivering the same message on Capitol Hill this week, the administration in part has hoped to head off what Sen. Max Baucus (D-Mont.) described as "creeping impatience" among lawmakers over the progress of the war.

Rep. Norman D. Dicks (D-Wash.) said he sensed "a little frustration" setting in among House members, but added that there has been no effort by the military to mislead members about the cost and duration of the war. "The military from the very start has been very sober about this," he said. But he added that it has become clearer to members that "there are limits of how effective the air campaign can be against ground forces. All of a sudden, a nice tidy, quick victory doesn't look like it's on the horizon."

Emerging from the White House meeting with the president, House Minority Whip Newt Gingrich (R-Ga.) was asked about the bravado of December, when the president had boasted privately that if war broke out, Saddam would "get his ass kicked." Gingrich responded: "I think he's going to get his butt kicked. It's just going to take awhile to finish doing it."

Staff writers David S. Broder, Ann Devroy, Helen Dewar, Barton Gellman, Gwen Ifill, Haynes Johnson, Tom Kenworthy, George Lardner Jr., foreign correspondent Nora Boustany in Jordan, special correspondent Trevor Rowe at the United Nations and staff researcher Lucy Shackelford contributed to this report.