U.S. Sending Another 300 Warplanes to Gulf : Military: The Pentagon moves to beef up Air Force armada by a third. It’s part of new shift to the offensive.

The Pentagon, building its forces for possible offensive action after Jan. 15, is sending another 300 warplanes to the Persian Gulf in a move that will increase the U.S. Air Force armada in the region by fully a third, defense sources said Thursday.

The aerial reinforcement, part of a new shift toward offensive capabilities, clearly underscores the U.S. military’s intention to make massive use of air power early in a potential conflict with Iraq in hopes of avoiding a bloody ground war.

The new wave will include a second squadron of F-117 Stealth fighters and additional F-15E ground-attack jets, F-16 fighters, A-10 tank-killers, refueling tankers and RF-4C photo-reconnaissance planes, the sources said.

In all, 27 more Air Force units with about 10,000 additional personnel will be dispatched to the region starting as early as this week. A number will be redeployed from Europe, and others will come from U.S.-based Air National Guard and reserve squadrons.

The latest deployment will boost the number of U.S. Air Force planes in the gulf to 1,200, with some of the additional planes to be stationed at a new Saudi base outside the capital of Riyadh.

The Marines and Navy have an estimated 700 combat aircraft in the theater or en route, while the Air Force already has about 900 combat and support airplanes.

Defense Secretary Dick Cheney indicated three weeks ago that additional Air Force warplanes would be sent to the region when he announced that the United States was beefing up its force there by 200,000 troops. But the extent of the new Air Force deployments has not been revealed previously.

Officials said that the substantial new numbers of aircraft will give the U.S. force in Saudi Arabia greater offensive power, as well as an ability to sustain prolonged combat operations.

In addition, sources said, U.S. military officials are negotiating with governments in the Middle East to establish a base for B-52 heavy bombers so that they will be closer to the front if war breaks out. The closest B-52s are now based nearly 3,000 miles from Kuwait, on the island of Diego Garcia in the Indian Ocean.

Countries with bases that could host the long-range bombers include Saudi Arabia, Turkey, Oman, Egypt and Sudan.

Pentagon sources said that any American ground attack would be preceded by days--perhaps weeks--of intense, round-the-clock aerial bombardment designed to destroy Iraqi air defenses, pulverize ground fortifications and terrorize and demoralize Iraqi troops.

The first targets would be Iraqi anti-aircraft missile batteries and their command-and-control centers, including the central air defense headquarters in Baghdad, sources said. The radar-evading Stealth fighters and the powerful F-15E attack jets equipped with air-to-ground guided missiles would be heavily employed in this first phase, Pentagon strategists indicated.

Meanwhile, military commanders in Saudi Arabia are stepping up their training to emphasize offensive operations on the ground and in the air, including large-scale tank maneuvers and simulated attacks on fortified positions like those established by Iraqi forces in Kuwait.

“We’re all sort of expanding our horizons, if only to give the new forces room to maneuver,” said Lt. Gen. Walter G. Boomer, commander of the Marine force in Saudi Arabia and nearby waters. By mid-January, the Marine Corps is expected to have nearly two-thirds of its total force in the gulf region.

In the air, planes designed to support the forward thrust of tanks have stepped up training flights, while fighter aircraft have intensified their scrutiny of potential Iraqi threats from ground-based missiles and fighter aircraft.

Air Force support units have begun stockpiling spare parts and ammunition adequate to support several hundred combat sorties per day. While supplies of fuel and ammunition are considered adequate for a strenuous air campaign, commanders fret about potential shortages of spare parts and electronic gear likely to be consumed in large numbers in combat.

On the ground, the shift to offensive planning already has caused a transformation as commanders who until a few weeks ago had given top priority to defensive missions now focus on ways in which U.S. forces might mount an offensive against Iraq.

From new trench-breaching practice at the platoon level to top-level planning at central headquarters, the shift is understood to focus primarily on ways to overcome the Iraqi fortifications that represent the most formidable barrier to a ground attack.

While new U.S. units will soon arrive to virtually double the ground forces here, the primary role in any U.S. offensive is expected to be played by long-established units that have already had months to become accustomed to the desert.

At the same time, however, the arrival of the new troops is expected to extend American front lines many miles westward. This would present a new, broader threat to Iraqi defenders who previously could focus on a relatively narrow American area of operations. It would also ready fast-moving U.S. ground troops to speed into Kuwait and cut Iraqi troops off from their supplies and their avenues of retreat to Iraq.

The transition from defensive to offensive training has been relatively easy, Army commanders noted, because American military doctrine makes little distinction between the two types of combat. Even when a unit is defending against an enemy attack, it should be preparing to counterattack, Army officers said.

U.S. forces in Saudi Arabia recently have begun combined training with allied armies and are preparing large-scale air and ground exercises, some as large as division-sized. Tank and artillery units are working on complex gunnery drills against moving and stationary targets.

“There’s a lot of work on desert familiarization, navigation, communications,” a senior Army officer said. Troops are also working on bridging, demolitions and breaking down fixed defenses, he said, in preparation for the possibility that they will be forced to assault the elaborate Iraqi defensive positions in Kuwait and southern Iraq.

Times staff writer Douglas Jehl contributed to this report from Saudi Arabia.