RIYADH, SAUDI ARABIA, FEB. 7 -- The number of aerial raids against elite Iraqi Republican Guard forces and regular troops will increase dramatically in the coming days, senior allied military officials said today.

Bombers and attack planes have begun directing precision missiles and "smart" bombs at Iraqi artillery -- considered the most lethal threat to American and other allied ground troops, according to high-ranking military officials and pilots regularly flying attack missions over the battlefield.

Military authorities said warplanes will continue to attack bridges, railroad tracks and communications lines in an effort to strangle Iraqi ground forces, but officials said attacks will increasingly concentrate on the fighting tools of the Iraqi troops. Highest on the target list are the artillery and entrenched tanks of the Iraqi forces in Kuwait and southern Iraq, officials said.

"We've been isolating the battlefield," said one U.S. military official. "Now we're focusing energy on the forces we may have to fight. We're not going to fight in Baghdad, we're going to fight down here" in Kuwait.

The commander of the British forces in the gulf, Lt. Gen. Peter de la Billiere, told reporters today, "I believe the land war is inevitable." He added that allied troops are "now moving on to the next phase" in preparation for a ground war and said the air attacks of the past few days are "minor compared to what they've got coming."

Although U.S. military commanders quickly attempted to distance themselves publicly from the British assessment, the preparations for a ground attack are expected to dominate the agenda this weekend when Defense Secretary Richard B. Cheney and Army Gen. Colin Powell, chairman of the Joint Chiefs of Staff, meet with senior U.S. commanders here.

Pilots flying regularly over Kuwait and southern Iraq describe a perpetually changing environment, the product of repeated allied bombings followed by repeated enemy retrenchments.

"There are areas where they are digging in, there are areas where they have left in a hurry, and there are areas littered with broken, burned-out vehicles," Air Force Capt. Jon Engle told combat pool reporters. "Every day we go out and kill a few more tanks and knock out a few more artillery sites. And every day that's that many less tanks that our ground guys are going to have to face when they finally push on in."

Officials said the large concentrations of Republican Guard troops are entrenched on the northwestern Kuwaiti border with Iraq, while second-echelon troops are dispersed throughout Kuwait.

"We want to take him at his weakest points," said one military official, describing a possible ground assault against the forces of Iraqi President Saddam Hussein. "We'll isolate a pocket, then go around it -- it will be a high-tempo operation if it's ever executed."

Because Iraqi forces were highly successful in their artillery attacks against Iran during the eight-year war between those two nations, one senior U.S. commander said "artillery is a high priority in all echelons" of Iraqi forces, from the Republican Guard to the front-line forces in Kuwait near the Saudi border.

The highest-profile bombing against troop concentrations to date has come from B-52 Stratofortress strikes with 1,000-pound bombs. Bombs also available -- but not currently in use -- are "fuel-air explosives" that release a cloud of flammable mist just above the ground and ignite in a fireball that resembles a nuclear blast, and "gators" that sprinkle small mines on highways, creating a deadly hazard to vehicle convoys.

But pilots say these weapons -- tremendously effective against large targets -- do not perform as well against single artillery emplacements and tanks. For this, pilots have begun switching to more precise weapons -- laser-controlled "smart" bombs and rockets like the infrared-guided Maverick air-to-ground missile.

"An incredible weapon," said Maj. George "Jet" Jernigan, an F-16 attack-jet pilot who said he destroyed a tank with one of the missiles on Tuesday. "I wouldn't particularly want to be a tank driver on the other side right now."

Saudi fighter pilots, expressing boredom with escort duty and air patrols against an Iraqi air force that will not challenge them, have replaced some of their air-to-air missiles with Mavericks and have gone hunting for ground targets.

And the low-tech A-10 Thunderbolt II attack plane, which has no radar, uses the Maverick's cockpit video display to select targets for its other weapons. The Maverick system has become central to the A-10's unaccustomed role as a night fighter.

And as the air war moves from strategic "hard targets" to the "softer" troop concentrations and equipment, the allies are drawing more heavily on A-10s and other tactical attack aircraft designed for close air support of troops and for strikes against single targets on the battlefield. The A-10 has come to play an increasingly important role in the air war's transitional phase, winning praise as a hunter of single targets, including everything from artillery and tanks to fuel dumps and radar sites.

A week after the war began, A-10s in a single night destroyed six permanent Scud missile sites, three temporary sites and three mobile launch pads, according to military reports reaching combat pool reporters in the field.

On Wednesday, Air Force Capt. Bob Swain, 33, a reservist from Charlotte, N.C., became the first A-10 pilot in history to shoot down an enemy aircraft, shooting down an Iraqi helicopter with 300 rounds from his seven-barrel 30mm cannon -- a weapon designed primarily for use against tanks.

"I tried locking on with an AIM-9 {a heat-seeking Sidewinder missile}, but on the first pass I couldn't, so I used the 30mm," Swain told combat pool reporters. "Some of the bullets ran through him, but we weren't sure if it was stopped completely. So I came back with the final pass, hit it, and it fell apart." Swain said he couldn't identify the helicopter because "it was just in a bunch of little pieces."

Swain was flying over central Kuwait, where some 350,000 Iraqi troops are entrenched in sand-and-concrete bunkers and fortifications built and improved since Iraq's Aug. 2 invasion. The A-10 pilots, like those of any other allied aircraft over Iraq or Kuwait these days, are shooting anything that moves.

"We've gone from deep air strikes to battlefield air interdiction," said Marine Maj. Thomas J. McElrath of Pompton Lakes, N.J., pilot of a night-flying A-6 Intruder attack plane. "We're prosecuting any target that's out there."

And, judging from most reports, getting away with almost anything they try. A pair of F-15C pilots shot down two Iraqi planes apiece Wednesday after making only a perfunctory check to see if there were any other Iraqi aircraft in the vicinity.

"I felt kind of cautious for starters; we had to make sure there were no others around that we didn't see," said one of the pilots, who asked combat pool reporters to identify him only by his radio call sign, "Vegas." "I just ran on down there wondering whether we were going to get shot back at or anything like that. It was kind of nice when they didn't."

The four jets downed by Vegas and his partner, identified only as "Gigs," were the first Iraqi aircraft shot down while trying to escape to neighboring Iran, which has impounded more than 120 Iraqi aircraft in the last two weeks.

The downed planes -- two MiG-21s and two SU-25 attack aircraft -- were overmatched against the F-15s, whose role is to defend allied planes and airspace against any intruder. Until now, the escaping planes had been able to leave Iraq virtually unmolested, but Wednesday's incident suggested that the U.S. fighters, which had been flying for hours near the border before spotting the Iraqi planes, had been waiting in ambush.

As time has passed, Iraqi antiaircraft artillery and missile fire has declined steadily, according to pilots and military briefers. Increasingly, the allied air war's principal job against the Republican Guard and the Iraqi troops in southern Kuwait is to select the weapons and the methods that will inflict the most damage in the shortest period of time.

Still, pilots remain leery of Iraqi artillery and rockets. "Every night we go out, and it's like, is this the night he's going to bring up his radar and try to bag us?" McElrath said.

"If you go too low," added another pilot, "even the Iraqis reward stupidity."

Journalists covering the Persian Gulf War from Saudi Arabia operate under rules of the U.S.-led military command. Small groups of reporters are assembled in pools and, with military escorts, are given access to military sources in various locations. The journalists' reports must be reviewed by military censors. Some information in today's editions was gathered under those conditions.

Type: Single-seat attack aircraft

Length: 54 ft., 4 in.

Maximum level speed: 423 mph

Operational range: 288 miles (combat radius)

Description: Built by Fairchild Republic Co., the low- and slow-flying A-10 "Wart Hog" is one of the Air Force's chief anti-tank weapons. Construction and design were driven by three requirements: ability to deliver a heavy weapons load, capacity to fly with little maintenance and ability to survive constant, treacherous antiaircraft fire.

A huge seven-barrel 30-mm cannon fitted into the fuselage below the nose can shoot 4,200 rounds of armor-piercing shells per minute. The extremely dense depleted-uranium projectiles travel at more than 3,280 feet per second.

Aircraft systems are duplicated and widely spaced so that injury to one will not damage another. The A-10 can theoretically fly with one engine, flap or tail unit completely shot away.

Cockpit area, flight control systems and engines are encased in titanium armor plating for protection. The titanium tub protecting the pilot weighs 700 pounds.

Position of General Electric turbofan engines makes them less vulnerable to small arms fire from the ground. Engines have no afterburners or hot exhaust -- easy targets for infra-red homing missiles.

Maximum weapons load of 16,000 lbs. can include AGM Maverick air-to-ground missiles, conventional and laser-guided bombs, rocket pods, gun pods, Sidewinder air-to-air missiles.

Main landing gear projects slightly even when retracted, permitting belly landings with limited damage to fuselage and wings.

Compiled by James Schwartz, illustration by Johnstone Quinan -- The Washington Post

SOURCES: Combat Mission; Periscope data base; Jane's All the World's Aircraft, The Encyclopedia of World Air Power.