WASHINGTON (AP) _ If President Bush unleashes U.S. firepower in the Persian Gulf, the first blows against Iraq probably will be inflicted by U.S. stealth fighters and strike planes that can drop a million pounds of explosives a day.

An air assault by coordinated U.S. and allied forces is expected to start any offensive because it would ease the way for allied ground forces to try to retake Kuwait, where Iraq has deployed a heavily fortified army of at least 540,000 men.

Iraq's air force is outnumbered 2-1 and lacks the sophisticated weaponry and support systems used by U.S. warplanes. But it has formidable anti- aircraft defenses, including American-made Hawk surface-to-air missiles that Iraq captured from Kuwait when it overran the tiny emirate last Aug. 2.

Iraq also has thousands of hand-held anti-aircraft missiles and guns in and around Kuwait.

The allied forces recently opened an air base in central Saudi Arabia, bringing five squadrons of F-15E Eagles and other warplanes within closer reach of targets in Kuwait and Iraq.

U.S. military experts generally agree that the American-led force could win control of the skies within days, but a tougher question is whether air power could make the difference in pushing Iraqi ground forces from Kuwait.

Jack Merritt, a retired Army general who is chairman of the Association of the U.S. Army, said Thursday that U.S. military leaders can't be sure air power alone would defeat Iraq, but that it will play a crucial role.

''If they (the Iraqis) feel totally defenseless against our air, their morale in very short order might collapse,'' leading to a quick retreat from Kuwait, Merritt said in an interview. ''But you could not count on it.''

The Pentagon won't publicly discuss war plans, but military experts say a nighttime aerial assault probably would begin with strikes deep inside Iraq. It is a mission tailor-made for the F-117A stealth fighter-bomber that saw its first combat action in the December 1989 invasion of Panama.

The stealth planes, specially built with composite materials the Air Force says make the aircraft virtually invisible to radar, could team with other low-level bombers and strike fighters to hit the communications and command centers that link Baghdad to the front lines.

At nearly the same stage in the initial aerial bombardment, other strike aircraft, including U.S. F-15Es, the Navy's carrier-based A-6 Intruders and perhaps British Jaguar ground-attack jets, would try to knock out Iraq's defenses. Main targets would be Iraqi warplanes and surface-to-air missile batteries.

In the five months since Iraq invaded Kuwait, the United States has assembled in the gulf area a force of tactical air power greater than that deployed in Europe during the Cold War.

''Every system we own is there,'' said Lt. Col. Michael R. Gannon, an Air Force spokesman.

In all, about 1,300 aircraft from the Air Force, Navy and Marine Corps are deployed in the gulf area, including about 400 warplanes on six aircraft carriers.

The Air Force will not publicly confirm that it has sent B-52 long-range bombers to the area, but military sources speaking on condition of anonymity say at least one squadron is based on the Indian Ocean island of Diego Garcia.

The venerable bombers would be used to conduct saturation bombing of Iraq's deeply dug-in armored columns inside Kuwait after more agile aircraft had cleared the skies and knocked out Iraq's main air defenses.

Besides an estimated 44 stealth fighter-bombers deployed in Saudi Arabia, the Air Force has nearly an equal number of F-111 supersonic bombers at a base in southern Turkey, within range of Iraq.

Also deployed are F-16 Fighting Falcon jet fighters; A-10 Thunderbolt II planes designed to hit tanks; F-4G Wild Weasel planes to seek out and destroy enemy anti-aircraft artillery and missile sites; and hundreds of refueling aircraft, reconnaissance planes and electronic warfare aircraft.

Critical to the success of a coordinated air attack on Kuwait and Iraq would be the role of the Airborne Warning and Control System, or AWACS, aircraft, which can detect, identify and track enemy and friendly planes.