DHAHRAN, SAUDI ARABIA, JAN. 29 -- U.S. Marine Harrier jet fighters and other allied warplanes attacked an Iraqi convoy just inside Kuwait's border with Saudi Arabia on Monday night and destroyed 24 tanks, armored personnel carriers and trucks, U.S. military officials said. The raid was part of the effort by air and ground forces to weaken -- and unnerve -- Iraq's front-line troops.

The attack, which officials said had been directed at least in part by spotters on the ground in Saudi Arabia, "was the first hard kill we've gotten on a big target," Marine Col. Ron Richard told reporters. Richard said the convoy appeared to have been conducting a routine movement behind its lines, not an advance on allied forces. "They got sloppy and got caught."

Flames from the burning vehicles could be seen for miles across the flat desert early today.

Allied air forces appear to be growing more confident as they conduct such attacks and slowly suppress Iraq's air defense network. Meanwhile, the war is beginning to seep across the border on the sands below, with ground troops on both sides apparently increasing harassment of their enemies.

This week, a dozen Iraqi soldiers slipped across the border into Saudi Arabia and ambushed a Saudi patrol in a barrage of gunfire and rocket-propelled grenades, according to a U.S. press pool report. One Iraqi officer was killed by fire from his own troops in the skirmish and three Saudi troops were slightly injured before the Iraqis dashed back across the border, leaving trails of blood, the report said.

"It was not a professional ambush,"said one U.S. officer.

But another cautioned: "They're coming across the border, which means patrolling is a lot more dangerous. The ante is upped."

Under a silvery full moon late Monday night, a small band of scouts from the 82nd Airborne Division blackened their faces with camouflage paint and sneaked into the no man's land at Saudi Arabia's edge, according to an account from pool reports. They advanced to within about four miles of an Iraqi artillery post, the reports said.

The paratroops were performing their nightly task of piecing together bits of information about the terrain and the Iraqis' position. Each night, they travel to the point of the previous night's furthest advance, then they creep to new watchposts closer to Iraqi lines.

As they advance, often crawling on their bellies in the damp sand, they played out behind them a communications wire from their base camp, leaving it in place to eavesdrop on the border and to offer a communications line during a future assault. "We want to assess their strengths and weaknesses without being seen," their operations officer, Maj. Ralph Delosua, whispered into the frosty night air.

Spec. Hiram Sanders of Brooklyn, N.Y., explained that the scout teams sought to avoid contact with the Iraqis. "We're not supposed to get into firefights," he said, noting that their mission is "to snoop."

As gunners peered ahead through the thermal night-vision sights of anti-tank TOW missiles, the scouts pinpointed their location with a hand-held monitor that fixes the spot via laser communications with a satellite.

"The adrenaline is pumping a little bit more," said Sgt. Joe Brewer of Zurich, Mont., squad leader for the scouts. "You don't know what will happen out there."

Also Monday, U.S. officers reported, the Army's 1st Armored Division used the Advanced Tactical Missile System (ATACMS), firing one of its medium-range ballistic missiles early Monday at a target in Iraq that the officers did not identify.

The missile, with a range of 280 miles, is designed to be highly accurate, exploding over its target to scatter hundreds of grenade-like bomblets over an area larger than a football field. It is used on targets such as command posts and concentrations of troops and armor.

The firing surprised some U.S. forces, who thought they were under attack by an Iraqi Scud. Lt. Tom Doyle said he did not learn the rocket was friendly until five minutes after he saw it streak across the sky.

Iraq and allied forces have traded artillery fire across the border almost nightly since allied forces began air raids on Iraqi forces. And in the 13 days since then, allied ground troops have been preparing for what may await them on the other side of the border when -- as field commanders expect -- they are ordered to begin their assault.

The grunts of the U.S. military call the broad swath of Iraqi-held territory ahead of them "the killing zones." They contain vast mine fields with with explosives that can blast a 60-ton tank five feet off the ground and "Bouncing Bettys," whose shrapnel-laden charges are made more deadly by being propelled out of the ground to explode at waist height. The mines also include "toe-poppers," which explode with just enough power to rip the foot off a soldier.

Iraqi forces are believed to have planted more than a half-million mines in the sands of Kuwait, many of them as part of the prickly barriers of buried butane storage tanks, oil-filled trenches and 12-foot sand berms that protect Iraq's deeply entrenched infantrymen.

Marines have been sitting through briefings on the mine danger. As one gruff U.S. Marine sergeant conducted his third drill of the morning in mine detection, he explained to the troops, "The reason for all this is so that when your buddies disappear in a big pink mist and body parts are flying, you'll know what to do."

No matter how successfully the bombing "softens" Iraqi forces, the engineering teams and infantry units who will open a path through the mine fields for the tanks behind them face one of the war's most dangerous missions. Precision air and artillery strikes are designed to clear out most of the mines, but officials expect that 10 to 20 percent will survive.

Engineering units using reinforced bulldozers, tanks pushing large shovels and troops using World War I mine-detecting technology are to clear the fields for U.S. Bradley Fighting Vehicles and M1A1 tanks, military authorities said.

"Kuwait is going to be turned into one big minefield," said Marine Maj. George Cutchall, a mine expert. He said satellite photographs indicate that in the two weeks between Dec. 19 and Jan. 5, Iraqi troops laid mines in a 36-mile belt behind border defenses in eastern Kuwait. There are signs, he said, that another belt is being laid near Kuwait City.

But while the Marines train just outside of Iraqi artillery range and air assault teams, such as the Army's 82nd Airborne Division and 101st Air Assault Division, inch closer to the border, commanders of the heavier fighting units say they still are not ready for war.

Commanders for the Army's 3rd Armored Division said they are still struggling to assemble helicopters, tanks and other equipment that has arrived in the northern Saudi desert from the division's bases in Germany. Some helicopters remain aboard a cargo ship that had mechanical problems and was forced to stop at Malta, officials said.

Army officials said only about half of the division's troops and barely one-third of its tank-assault helicopters and heavy armor were ready for combat as of this weekend.

"I want to go to war with all my stuff," said Col. Charles Burke, 45, of Denver, Colo., the division's senior aviation officer. "There's no reason for us to rush" into a ground war.

The members of a large German-based U.S. Army transportation unit are still awaiting the arrival of critical trucks and other vehicles. The civilian crew of the United Arab Emirates-flagged vessel carrying the gear has refused to enter the Persian Gulf because of fear over the outbreak of war.

Military Sealift Command spokeswoman Marge Holtz said the equipment is being loaded onto another vessel in the Arabian Sea. She described it as an "isolated incident" among the 365 trips U.S. and allied ships have made to the Persian Gulf delivering more than 6.5 million tons of weapons, ammunition and equipment to support the war.

Senior military commanders in the region warned in December that troops and equipment arriving in Saudi Arabia from Germany would not be fully prepared for war until mid-February. Top military leaders here have said they believe the air war will continue several more weeks as allied forces try to weaken Iraqi forces and cut the number of casualties that would be suffered in the ground assault.

Army and Marine commanders here have said they have never believed that the coalition forces could reclaim Kuwait without some form of ground war. "There isn't anybody except an infantryman who can clean those guys out of a trench," said Capt. Keith George, commander of an armored calvary company. "Whether the Air Force does good or bad, we're still going."