Iraq Thursday fired two Scud missiles in the direction of a large Saudi military facility, but one was intercepted by a U.S. Patriot missile and no injuries were reported, Saudi and U.S. officials said.

U.S. military officials said the Scuds were fired about 5:08 p.m. from a point in central Iraq toward the King Khalid Military City, touching off air raid sirens in north-central Saudi Arabia.A spokesman for the Saudi military said a Patriot missile intercepted one of the Scuds and that the debris fell near the town of Hafar al Batin apparently without causing any injuries or damage.

The second Scud fell harmlessly into the desert, the spokesman said.

The incident marked the first Scud firing into Saudi Arabia since Saturday, when a missile launched toward the coastal city of Jubail broke up in midair without causing any damage.

After two nights of heavy bombardment, weary residents of Baghdad had a night free of allied air attacks. The Iraqi occupiers of Kuwait did not.

In a midday communique, Iraq's military said the allies carried out more than 320 raids on military targets in the southern war zone over the past 24 hours - more than three times the number reported the previous day.

The Iraqi military communique also claimed Iraqi forces inflicted "substantial losses" on the allies with missile strikes on front-line positions.

The U.S. command said Thursday two Americans were killed in the crash of an Army OH-58 scout helicopter overnight while returning from combat operations along the border.

The command said two other U.S. aircraft also were lost, an Air Force F-16 fighter-bomber that crashed after suffering engine failure while being refueled in flight, and a Marine CH-46 helicopter that was wrecked in an emergency landing. The F-16 pilot ejected and was rescued. One helicopter crewman suffered a broken leg, the command said.British army Col. Barry Stevens said Britain's 1st Armored Division engaged in its heaviest artillery shelling of Iraqi positions Thursday.

He said the division's entire artillery contingent participated - 72 guns and 12 MLRS (multitube rocket launchers). They fired 1,300 cannon shells and 144 rockets, he said.

On Wednesday, the U.S. military reported intensified fighting along the Saudi frontier, including artillery duels and allied incursions into enemy territory.

In one clash, Iraq lost five tanks, 20 artillery pieces and an unspecified amount of men, while one American was killed and seven wounded by Iraqi fire, the U.S. military command said.

The U.S. Central Command spokesman, Marine Brig. Gen. Richard Neal, said Wednesday his soldiers were "ready to go right now - or they can go in two weeks."

A military official in Washington, insisting on anonymity, said all that was needed was an order to go.

"We are in the eye of Desert Storm," the official said.

Allied pilots flying missions over Kuwait reported continued success knocking out Iraqi armor. Despite a month of round-the-clock bombing of Iraqi positions, U.S. ground forces still face a formidable, entrenched army, the airmen said.

"Anyone who thinks it's going to be two days, or three days, or five days, I think is crazy, just because of sheer numbers of people," said Capt. Bradley Seipel, a weapons system officer of an F-111. "It's kind of like the people saying the air war would last five days."

U.S. officials said Thursday about 300,000 Iraqi troops in the Kuwait theater - 10 divisions, plus the 150,000-member Republican Guard - still appear to be in fighting form.

At the front, Sgt. Jose Roche, 28, whose Marine company is dug in within sight of border fortifications, said troops are expecting close combat.

"Biting, kicking, scratching, whatever it takes," he said. "When you're fighting hand-to-hand, it's just a street fight."

A grimmer scenario is Iraqi use of chemical weapons - which U.S. commanders say they expect once a ground assault begins.

"I pray it's not going to happen, but, yes, I'm convinced they're going to use chemicals," said Col. Samuel Raines, commander of the Army's 7th Engineer Brigade.

Battlefield intelligence suggests Iraqis may fire rocket-propelled grenades filled with cyanide gas. Chemical weapons also could be connected to land mines or sprayed from helicopters, commanders said.

A member of the exiled Kuwait government claimed occupying Iraqi forces have stepped up killing and torture of Kuwaitis in the last two weeks, concentrating on women, children and detainees.

An Iraqi military spokesman scoffed at statements from the allied commander, Gen. H. Norman Schwartzkopf, that coalition troops captured hundreds of Iraqi troops Wednesday.

"We were surprised to hear such statements full of mistaken information coming from Schwartzkopf," the Iraqi spokesman said. "Such actions happen only in American movies."