Three of every four allied airstrikes are now targeting Republican Guard forces that stand between advancing columns of U.S. ground troops and Saddam Hussein's government, a top American air officer said in an Associated Press interview Saturday.

From his desert command post in Saudi Arabia, Air Force Brig. Gen. Daniel Darnell also said U.S. and British warplanes over the past week have attacked virtually every military airfield in Iraq — believed to number roughly 100 — and have seen only a small number of planes.

Intensified allied airstrikes on Saddam's best ground forces coincide with efforts by the Army's 3rd Infantry Division and the 1st Marine Expeditionary Force to consolidate their supply lines south of Baghdad before beginning a multipronged assault on the Republican Guard.

The intent is to severely weaken those forces so they will fall more quickly to American ground troops, minimizing U.S. casualties.

The air campaign against the Republican Guard ringing Baghdad intensified after the foul weather that had impeded air operations lifted a few days ago. Darnell said there will be no letup in airstrikes.

"That will increase at least a little more" in the days ahead, he said. The coalition has flown roughly 1,000 missions a day in recent days.

Army attack helicopters are joining the battle. More than 40 Apache helicopters from the 101st Airborne Division launched Hellfire missiles and other munitions in an attack Friday on elements of the Medina division of the Republican Guard, Maj. Gen. Stanley McChrystal said at the Pentagon.

McChrystal said the Medina division is trying to stay clear of U.S. air power, which is "taking them apart, piece by piece."

Darnell said the Iraqi air force, which was vastly depleted in the 1991 Gulf War, has not flown a single mission since this war began March 20. While that is good news for allied pilots, Darnell said he and other air war planners remain wary of the potential for Iraqi surprises.

The Iraqi air force is believed to have no more than 100 serviceable combat aircraft.

The United States has more than 600 aircraft in the region, as well as about 30 ships and submarines that have launched more than 650 Tomahawk cruise missiles.

Darnell is director of a command post at Saudi Arabia's Prince Sultan Air Base that runs all aspects of the air campaign. Known as the Combined Air Operations Center, it is headquarters for Darnell's boss, Lt. Gen. Michael Moseley, the top air commander in the Persian Gulf.

In the telephone interview, Darnell disputed suggestions from some critics that the air campaign has failed to achieve its intended goals.

"We're on track thus far," he said, while acknowledging that some thought victory would come quickly. He said the military challenge is bigger than in the 1991 war, in which the air campaign lasted five weeks before allied ground forces prevailed in 100 hours of combat.

"We're faced with a much larger problem" this time, given that the entire territory of Iraq is a battlefield, whereas the 1991 conflict was focused on expelling the Iraqi army from tiny Kuwait.

"Any insinuation or opinion that the air effort is not meeting objectives is misplaced," said Darnell, whose prewar assignment was commanding the Air Force's largest flying unit, the 57th Wing at Nellis Air Force Base, Nev.

Darnell said he could not estimate what proportion of Iraq's formidable surface-to-air missile force has been destroyed or disabled by the bombing. "I would be totally guessing," he said.

Darnell said the Air Force's approach to war is based less on counting the number of structures and weapons its destroys than in assessing the effects those attacks have on the opponent's ability to command and control its forces.

The key effect sought in this war, obviously, is the loss of Saddam's control over Iraq. Darnell declined to estimate the degree to which Saddam may be losing his grip on power, although he said airstrikes against the pillars of power in Baghad are having "some of the desired effects."

He said it has become harder for Iraq's leaders to communicate with each other and to their forces.

In the early days of the air war, strikes against Saddam's presidential compound, his communications centers, intelligence headquarters and other strategic targets were the main focus. But in recent days much of the focus has shifted from Baghdad to the Republican Guard on the outskirts of the capital.

By Friday, 75 percent of all air missions were targeting elements of the Medina and other Republican Guard divisions, he said. The rest are against targets inside Baghdad and in support of U.S. ground forces operating in western, northern and southern Iraq, Darnell said.

The air command post at Prince Sultan directs not only Air Force missions but also those of Marine Corps and Navy flights, including those flying from the five aircraft carriers in the region.

Rear Adm. Barry Costello, commander of the USS Constellation battle group in the Persian Gulf, said Saturday that his planes are pounding Republican Guard positions south of Baghdad. He said they hit 40 targets in the past 24 hours, including a Republican Guard headquarters near Kut.

The bulk of close to 100 bombing missions a day from each of the five carriers have been at night and have hit artillery, command posts and vehicle convoys of the Republican Guard's Medina division, Navy officials said.