President Bush yesterday pledged "the darnedest search and destroy mission that's ever been undertaken" against Iraq's remaining Scud missiles as part of an intense military and diplomatic effort to keep Israel out of the Persian Gulf War.

U.S. and allied bombers combed western Iraq to try to wipe out the Scuds and prevent Iraq from again attacking Israel. U.S. aircraft reported destroying at least six more Scud launchers. The United States also offered to rush additional Patriot missile batteries to Israel to help protect its cities from the kinds of attack that struck Haifa and Tel Aviv Thursday night and brought Israel to the brink of a decision to enter the war.

The swift retaliation by allied aircraft, coupled with intensive U.S. diplomatic efforts that included a phone call from Bush to Israeli Prime Minister Yitzhak Shamir, apparently persuaded Israel to refrain from immediately striking back at Iraq. Air raid sirens twice sent thousands of Israelis to shelters again last night, but the threats proved to be false alarms.

Israeli anxiety was mirrored in Washington, where U.S. officials said that urgent calls to Israeli officials Thursday night and yesterday produced no firm commitment by the Israelis on what they would do. If Iraq succeeds in another missile attack -- as many Pentagon officials believe is possible -- White House officials doubt the Israeli restraint will continue. One official said there was "constant contact" with the Israelis to prevent the war from growing into an even larger regional conflict that could shatter the allied coalition in Operation Desert Storm.

Bush urged the American people to resist the euphoria spawned by the first successful hours of the war. "We must be realistic," he said at a White House press conference. "There will be losses. There will be obstacles along the way. And war is never cheap or easy."

Senior military commanders echoed the president's caution, stressing the war had only just begun. "That large army is still sitting there and it has to be rooted out," Lt. Gen. Thomas Kelly, senior operations officer for the Joint Chiefs of Staff, told reporters yesterday.

Allied aircraft losses now total eight, including four U.S. planes with seven crew members listed as missing. Intense search and rescue operations are underway, said Pentagon spokesman Pete Williams.

Pledging that the United States and its allies would prevail in their objective of driving Saddam's forces from Kuwait, Bush said: "I can guarantee the world that as every hour goes by, he is going to be less able to respond, less able to stand up against the entire world."

Bush's optimism evidently was shared by world markets. The price of oil continued to tumble yesterday, falling more than $2, closing at $19.25 a barrel on the New York Mercantile Exchange. That price was the lowest since last July. Oil companies continued to cut the wholesale price of gasoline, which eventually should be reflected at the pump.

Although the second day of the Persian Gulf War included hundreds of sorties against Iraqi air defenses and other targets, the centerpiece of the allied effort -- in urgency if not the actual number of bombing missions -- was the effort to destroy the Scuds.

U.S. officials believe that Iraq possesses about 30 Scud launchers, but the number of reloads -- extra missiles -- is uncertain. U.S. intelligence estimates put the Iraqi Scud stockpile at 300 to 1,000. "They've been squirreling them away for years," one senior offical said. The allied bombers are searching for the Scuds with satellite imagery and special reconnaissance aircraft capable of detecting heat-emanating weapons.

"Finding the fixed launchers is a relatively easy business, but finding the mobile launchers is like finding a needle in a haystack," said Gen. H. Norman Schwarzkopf, commander of the allied force in Operation Desert Storm.

Allied bombers Friday morning found and destroyed six of the mobile launchers with Scud missiles aboard aimed at Saudi Arabia; five other launchers had been located and were being attacked "relentlessly," Schwarzkopf said.

The allied air war has reached the planned plateau of about 2,000 sorties a day, Schwarzkopf said; congressional sources said 5 million pounds of bombs were dropped in the first 24 hours of the war, a daily ordnance load roughly comparable to that of the intensive Christmas 1972 bombing campaign in Vietnam.

In the next several days, U.S. commanders expect additional Scud attacks on Israel and Saudi Arabia and Iraqi attacks against U.S. Navy ships, possibly using Exocet missiles fired from helicopters, the Pentagon told congressional officials.

The new Patriot missiles ordered to Israel yesterday will supplement two batteries already sent to the Jewish state earlier this month. Bush agreed to provide Israel with those missiles last fall under emergency military assistance laws, specifically citing the "increased threat from ballistic missiles in the Iraqi inventory."

But those batteries are not yet operational, Pentagon officials said, citing delays in shipment and in training air defense officers in the operation, maintenance and tactics of the complex system. Other experts suggested that the delays also reflected friction between the United States and Israel over how much control Americans would retain over the weapons.

Designed as an antiaircraft missile, the Patriots sent to Israel were already modified to serve as anti-missile interceptors, officials said. A Patriot shot down an incoming Scud over the Saudi Arabian city of Dhahran early Friday morning.

The false alarms that triggered the air raid sirens in Israel yesterday were based on warnings from U.S. intelligence, a senior Pentagon official said. American reconnaisance detected signs of an attack on Israel, although no Scud was actually launched. An Israeli military spokesman said the second alarm was triggered by a suspicious object which turned out to be a Soviet satellite.

U.S. warplanes began flying attack missions from Turkey following a vote by the Turkish parliament to permit offensive operations during Operation Desert Storm. Those planes, according to one official, were likely being used in the hunt for the Scuds.

Eleven Iraqi planes -- out of an air fleet of roughly 700 -- have been confirmed as shot down or destroyed on the ground, although others are believed to lie beneath the rubble of demolished hangars and shelters, Pentagon sources said. U.S. B-52s continued to strike elite Republican Guard troops and other targets, although only 10 to 20 tank kills -- of more than 4,000 tanks in Kuwait and southern Iraq -- have been confirmed, the congressional sources added.

Kelly, senior operations officer for the Joint Chiefs, told reporters that U.S. weaponry has "performed stunningly well" and that "we think we're doing pretty well" in following the allied battle plan.

A key unknown, military sources said, is whether the intensive bombing will demolish Iraqi morale enough to undermine the army's fighting ability in a subseqeunt ground war. Allied forces are tring to cut water pipelines to some Iraqi troops, one source said, because "water's their big vulnerability."

The Navy also disabled or sank three Iraqi patrol boats, including a 147-foot missile boat with a crew of 35, Pentagon sources said. In the first two days of the war, U.S. Navy ships fired 196 Tomahawk cruise missiles, most targeted at reinforced targets.

Air Force B-52s, escorted by F-15 fighters and Marine FA/18 bombers, continued to strike eight divisions of elite Republican Guards in northern Kuwait and southern Iraq yesterday, Pentagon officials said. The bombers attacked corps and division headquarters, while A-10 attack planes hit Guard tanks. More than 500 sorties have been flown against the Guards.

Schwarzkopf and Bush both took pains to reiterate that Saddam personally has not been targeted except as part of a general effort to destroy the Iraqi command and control structure -- an effort which has included intensive bombing of the presidential palace in Baghdad and other sites Saddam is known to frequent.

Pentagon officials said that denying Saddam is a target is intented to preclude the ridicule that befell the military after Gen. Manuel Noriega managed to elude capture for a time after the otherwise successful invasion of Panama; in effect, Saddam is a prime target but U.S. officials believe that chances of killing him are marginal at best.

"We believe {Saddam} still is maintaining control over all elements of his armed forces," Rear Adm. John M. McConnell, the senior intelligence officer for the Joint Chiefs of Staff, said yesterday.

Bush signed an executive order yesterday afternoon allowing the Pentagon to keep military reservists on active duty for more than 180 days and call up to 1 million reservists to active duty. The Pentagon had requested the order because some reserve units activated at the beginning of the crisis in August were nearing their 180-day limit. Defense Secretary Richard B. Cheney said last week that he had no plans to use the authority to significantly increase the number of reservists called to active service.

Earlier yesterday, Bush said he had "thoroughly discussed" developments in the gulf yesterday morning with Soviet President Mikhail Gorbachev. The call from Gorbachev came after the Soviets had condemned the Iraqi attack on Israel, an unusual turn for a country which once was Iraq's patron and Israel's enemy. Deputy Foreign Minister Alexander Belonogov said in a statement that Saddam clearly was attempting to involve Israel and "inflame the conflict," warning that the Iraqis were on a course that "will lead . . . to disaster."

The unprecedented marriage of modern weapons technology and television brought the war into American living rooms yesterday as millions of viewers watched a remarkable video sequence of U.S. laser-guided bombs destroying Iraqi runways, air defense buildings and an air force headquarters in Baghdad. Other footage showed a Tomahawk cruise missile launching and a U.S. Patriot missile streaking from its cannister in Dhahran and destroying an incoming Scud with a blinding flash and a boom.

But detailed assessments of bomb damage and the performance of U.S. weaponry remained skimpy. Whether the video successes released by the Pentagon are representative or anomalous still is uncertain.

U.S. officials repeatedly have stressed their efforts to avoid killing civilians in the bombing raids, a policy which Pentagon sources said reflects both the political need to minimize non-battle casualties and a belief that Iraq will crumble faster if only military and industrial targets are hit.

Iraq reported 23 civilians killed in the first wave of attacks Thursday but has not released any casualty figures since. Baghdad Radio yesterday warned that "the war has just started....a war between good and evil." Iraqi Information Minister Latif Jassim told the Iraqi News Agency, "Not a few drops of blood, but rivers of blood will be shed." Iraq also claimed to have downed 94 allied planes, a figure disputed by U.S. commanders.

More than a dozen journalists who fled Baghdad and arrived in Jordan yesterday reported that Saddam's palace had been destroyed in a cruise missile attack and that the defense ministry also was demolished. Satellite dishes atop communications towers have been disabled and at least two military airfields in the Iraqi capital were crippled, the journalists said.

The bombing also appeared to leave a strong psychological scar on Iraqi civilians. "Even in the bomb shelters, the mood changed literally overnight," said Nigel Baker, a British television producer.

Anthony Massey, another British producer who left Baghdad yesterday, said: "The city appears virtually undamaged because of the accuracy of the cruise missile . . . . But it is completely deserted."

The Iraqi parliament's speaker, however, said hundreds of thousands of weapons had been distributed to Baghdad residents, turning the capital into "a jungle of fighters and trenches."

The war in the gulf continued to spark protests and prayer services in cities around the country, with two rallies planned for Washington today. The Associated Press estimated that more than 1,600 persons had been arrested nationwide since the war began on Wednesday night.

Yesterday's protests included: Indiana University students wrapped in body bags outside a military recruiting center in Bloomington, Ind.; sit ins at the University of California at Los Angeles and in Seattle; and a pro-Israel rally by about 200 members of a Zionist student group who carried U.S. and Israeli flags and chanted, "U.S. and Israel, together they cannot fail."

In Rochester, N.Y., protesters disrupted traffic as they chanted "No more killing, we're not willing," while marching through busy intersections.

In New York, four Roman Catholic archbishops celebrated a special Mass for Peace at St. Patrick's Cathedral. The four were Cardinals James Hickey of Washington, Bernard Law of Boston, Joseph Bernardin of Chicago and John O'Connor of New York.

Bush yesterday acknowledged the protests, but said, "This country is fundamentally united and I want that message to go out to every kid that is over there serving this country."

On Capitol Hill, the House voted 399 to 6 to approve a non-binding resolution expressing support for U.S. troops in the gulf and commending the "efforts and leadership" of Bush as commander-in-chief. The Senate approved an identical resolution on Thursday.

In Washington, for the second day, bomb threats, suspicious packages and abandoned cars had police responding to dozens of locations throughout the District. Dogs trained to detect explosives were taken through several buildings that were briefly evacuated, including the Brookings Institution near Dupont Circle NW. Nothing was found.

Staff writers Nora Boustany in Amman, Jordan; Jackson Diehl in Jerusalem, and Ann Devroy, Helen Dewar, Barton Gellman, David Hoffman, Tom Kenworthy, George Lardner Jr., Bill McAllister and R. Jeffrey Smith in Washington contributed to this report.