U.S. Jets Down 2 Iraqi Planes Fleeing to Iran : Gulf War: Two others are ‘possible kills.’ Exotic fuel-air weapons join the American arsenal.

RIYADH, Saudi Arabia —  The United States stockpiled exotic fuel-air weapons Wednesday for possible use in the battle for Kuwait, and allied officers said American jets intercepted Iraqi warplanes for the first time as they tried to flee toward Iran. American officers said at least two Iraqi planes were destroyed.

As an amphibious assault force of 18,000 Marines positioned itself for a possible attack into occupied Kuwait, reporters touring a U.S. air base on the Gulf saw stockpiles of weapons capable of spreading fuel mist and igniting it to create an explosion that some say is similar to a tactical nuclear blast.

An officer at the base, Maj. James McClain, said fuel-air explosives were new to the war. Pentagon officials have said that Iraq has also developed such weapons, capable of delivering a detonation several miles wide. “We have the ability to use all kinds of weapons,” McClain told reporters, “and that’s just one of them.”

The two downed Iraqi jets were described by Marine Brig. Gen. Richard I. Neal as Soviet-built SU-25s, among Iraq’s top warplanes. A Saudi military spokesman said American F-15s shot down four of seven Iraqi jets as they tried to dash to sanctuary in Iran. But Neal confirmed just two kills. He listed two MIG-21s as “possible kills.”

American officers said 10 Iraqi jets made it to Iran, raising the total that have sought refuge there to 120.

In other developments:

* A knowledgeable Pentagon official said allied warplanes are “tearing up” many units of Iraq’s select Republican Guard and have caused damage of “way over” 50% in some isolated cases. But he said other units remain “virtually untouched” and that the force overall “still might be able to fight.”

* Pilots who have been bombarding occupied Kuwait and Iraq for the past three weeks said they have run out of ready targets and have begun to cruise for targets of opportunity. They said the landscape has gotten so littered with battle damage that it takes as many as seven passes to find something worth destroying.

* Iran’s national news agency said allied air raids have caused severe food shortages in Iraq, forcing residents to pay 800 dinars (about $2,560) for a sack of flour. The flour is of poor quality, the agency said. But it said rationing has ensured families of enough food to keep starvation at bay.

Exotic Weapons

The presence of American fuel-air weapons in the Persian Gulf was reported in a pool dispatch cleared by allied censors. Under military rules, the location of the stockpile could not be specified. In the dispatch, reporters said that the weapons were unloaded only recently.

They said the weapons appeared to be awaiting transfer to storage in ammunition bunkers.

Fuel-air bombs are believed by some experts to be 10 times more powerful than conventional bombs. These experts call them “the poor man’s nuclear weapon.” But others say the bombs pack about as much punch as conventional explosives.

The weapons contain fuel, usually propane or ethylene oxide, in one or more separate canisters. An initial explosion disperses the fuel over the target, resulting in a massive cloud of gas and air. A second detonation ignites the mixture, creating a huge fireball together with a powerful shock wave.

Fuel-air bombs were used by U.S. forces to clear landing zones and minefields in Vietnam, and witnesses reported at the time that even small devices leveled patches of forest the size of a football field.

The devices are most effective in relatively flat regions--such as the desert--where shock waves would spread without interference.

A study by one fuel-air weapons designer describes a warhead capable of blanketing a wide area. The study depicts 100% fatalities across the area, with injuries decreasing to lung and eardrum damage in outlying areas. It describes major structural damage to refineries, aircraft and ships.

Also in view at the American base, along with the fuel-air weapons, were so-called “Gator bombs,” the pool dispatch said.

These are exploded in the air and disperse small mines.

Marine personnel said Gator bombs already have been used against Iraq and occupied Kuwait. The pool report quoted these Marines as saying the use was a “special request.” There was no elaboration.

The Marines said the Gator bombs are not currently being loaded on allied warplanes.

As the weapons were being readied, ships carrying an estimated 18,000 Marines moved into place for what could be the major amphibious assault of the war--most likely aimed at the Kuwaiti coast for a beach attack and westward push.

The Marines have been openly rehearsing their roles for weeks. If they do come ashore, it could be the biggest landing since the Marine attack at Inchon, during the Korean War in the 1950s.

The Air War

The downing of the two fleeing Iraqi jets marked the first time any have been destroyed while seeking sanctuary in Iran.

Allied officers differed about what happened.

A Saudi officer told reporters that four jets were downed and that three others made it across the border. But Gen. Neal, a spokesman for American forces, classified two of those four as only “possible kills.”

The American pilots who engaged the four Iraqi planes said, however, that they saw four fireballs--and no parachutes.

As the total of allied sorties in the war inched toward 50,000, the battleship Missouri again joined in the bombardment. It was the third straight day the battleship has fired on targets in Iraq and Kuwait. This time, American officers said, its massive guns destroyed a radar facility, a surface-to-air missile site and artillery positions.

The ship also fired at one other Iraqi target, officers said. They did not specify the nature of the target, but they said it was too well dug in for them to easily determine whether damage was inflicted.

Republican Guard

Assessing battle damage also was at issue in determining the remaining strength of Iraq’s elite Republican Guard.

On the eve of a trip to Saudi Arabia by Defense Secretary Dick Cheney and Gen. Colin L. Powell, chairman of the Joint Chiefs of Staff, to discuss the opening of a possible ground war to liberate Kuwait, a Pentagon official, who declined to be identified, said that Iraqi soldiers certainly have been “hurt” by heavy bombardment.

But the official added: “Hurt’s a relative thing. We’ve degraded him (the enemy), but we haven’t stopped him.”

Iraqi ground units, including the Republican Guard, continue to be supplied along routes that have been bombed and strafed in weeks of aerial sorties, the official said.

His statements dramatized the challenge that the allies face in deciding how effective three weeks of bombardment have been in creating conditions that would favor their ground troops and reduce casualties if they begin pushing the Iraqis out of Kuwait.

With half their combat vehicles destroyed, Iraqi ground troops would be largely ineffective as a fighting force, Pentagon officials have said. At that level of destruction, a senior official said, allied ground troops would face a “slugging match”--but a ground attack would be “do-able.”

At the Pentagon, Lt. Gen. Thomas W. Kelly, operations director for the Joint Chiefs, told reporters: “There has been damage done to the guard; we’d like to see more damage done to the guard, and that is why the bombing campaign is proceeding.”

In Saudi Arabia, Gen. Michel Roquejeoffre, commander of French forces in Operation Desert Storm, was quoted as saying that he believes allied air strikes have reduced Republican Guard effectiveness overall by about 30%.

Another French official had said earlier that he thought the guard remained about 95% intact, but Roquejeoffre said his assessment referred not simply to casualties among the elite troops but to the overall impact on its supplies, weapons and command structure.

Cruising for Targets

From the viewpoint of allied pilots, battle damage is heavy. They say they have exhausted readily available targets and are now searching for targets of opportunity.

“Every night we search, and every night it is more difficult,” declared Capt. Terry Featherston, an A-10 pilot from the 355th Tactical Fighter Squadron. He said the landscape in Iraq and Kuwait has become so scattered with the carcasses of armored vehicles that pilots take pass after pass to find something worth bombing.

Meanwhile, U.S. supply planes, in a rush to move fuel, equipment and food stocks toward the front in northern Saudi Arabia, have begun appropriating highways as makeshift airstrips.

In one case, engineers have detoured traffic around a one-mile stretch of desert highway and marked off a runway of just over 3,000 feet, complete with a loading ramp in the adjacent desert for a wing of C-130 Hercules supply planes.

Pilots in the 41st Tactical Airlift Squadron have been flying 12 to 13 hours a day, moving equipment from a major air base to the front.

If a ground assault begins, tactical airlift planes will move even farther forward to establish airstrips on captured Kuwaiti airfields, highways and dirt roads in order to carry water, fuel, food and ammunition to the advancing front lines.

In Iraq

The Iranian news agency blamed severe battle damage for food shortages in Iraq.

The shortages are particularly acute in Basra, the agency said. Basra, in the south, is the second-largest city in Iraq and has been hit daily by allied air raids since the outbreak of the war three weeks ago.

“In Basra,” the agency said, “most bridges, mosques, schools and residential areas have been destroyed. . . . Those who have fled say no one is immune anywhere in Iraq from the fire of U.S.-led forces.”

Allied officers deny targeting civilian facilities but say some might be hit by accident.

The Iranian news agency said 217 more foreign refugees entered Iran on just one night, between sundown Tuesday and dawn Wednesday, to seek shelter from allied raids.

In Baghdad, Bernd Debusmann, a correspondent for the Reuters news agency, reported in a dispatch cleared by Iraqi censors that allied air strikes destroyed a main bridge across the Tigris River.

The strikes, apparently by cruise missiles, knocked a 50-yard section of the Jumhouriya Bridge into the water on the south end of the concrete-and-metal structure and left two huge gaps in the northern end.

Streets on the northern end, in what once was part of Baghdad’s bustling business district, were littered with glass from windows blown out by the explosion, Debusmann said. Allied air raids have cut communications and electricity, he said. Reporters have seen residential areas in Baghdad and some provincial cities devastated by bombs and missiles, he said.

There was no overall figure on civilian casualties.

Debusmann said it was impossible to collect such data because the Baghdad telephone system has been destroyed. But he reported that one of the few diplomats still left in the city estimated civilian casualties in the thousands.

“These air attacks have thrown the country back decades,” Debusmann quoted one Baghdad resident as saying. “They are destroying everything of value. They want to wipe Iraq off the map.”

Contributing to this report were Times staff writers John Balzar in Dhahran and Melissa Healy and Paul Houston in Washington.

WAR ACTION

A. AIR WAR: U.S. jet fighters shot down two Iraqi planes--Soviet-made SU-25s--as they tried to flee to Iran.

B. FLEEING: In the past two days, at least 10 Iraqi fighter planes have fled to Iran; the total is now about 120.

C. MISSOURI: The battleship Missouri fired its 16-inch guns at targets along the Kuwaiti coast, destroying a radar site, artillery and a surface-to-air missile position.

D. GUARD: The U.S. reported that the elite Republican Guard, at the rear of the Iraqi lines in Kuwait, has shown great skill in dispersing and concealing its forces but is still being badly hurt by allied air strikes.

E. MARINES: Pentagon sources said a U.S. Marine task force--about 18,000 Marines--is maneuvering into position after a practice seaborne attack on the southern shore of the Arabian peninsula. The task force reportedly is “slowly making its way north.”