LUKE AIR FORCE BASE, Arizona — The four F-16 fighter planes lined up with military precision, wingtip to wingtip on the ramp in the desert heat, jet engines throttled back while the ground crews ducked underneath to give them last-minute safety checks. Then, one by one, the pilots taxied to the runway, went to full throttle, and roared into the air for gunnery and bomb training.

At the top of their tails, the F-16s carried white tailbands inscribed "Gamblers," the nickname for the 21st Fighter Squadron of the Republic of China Air Force on Taiwan. The Gamblers are posted permanently at this U.S. Air Force base for advanced training because they don't have the air space or the target ranges on their island home.

Moreover, USAF fighter pilots, a breed not known for reticence, claim that Luke AFB provides the finest training in the supersonic F-16 in a world in which more than 4,000 of the fighters are flown in 25 air forces from Bahrain to Venezuela. The F-16s may be best known for the Israeli air force raid into Iraq that destroyed Saddam Hussein's nuclear reactor at Osiraq in 1981. Every Israeli bomb hit the target.

Both Taiwan's Ministry of National Defense and the U.S. Air Force, however, were wary about discussing the squadron here. Both appeared anxious not to provoke mainland China, which claims sovereignty over Taiwan and has repeatedly complained about U.S. military cooperation with Taiwan. Moreover, a sale of 66 new F-16s to Taiwan is pending.

An officer in Taiwan's liaison office in Washington said in an e-mail that the Taiwanese pilots at Luke AFB could not be interviewed because that might upset negotiations over the F-16 sale. A USAF officer at Luke said in another e-mail that "due to political sensitivities with the 21st Fighter Squadron," the USAF would make neither American or Taiwanese pilots available.

Curiously, the Internet is awash with information and pictures about Taiwan's squadron at Luke AFB.

The Bush administration has evidently frozen the sale of the F-16s to Taiwan at least until after the Beijing Olympics in August to preclude irritating China. The question then arises whether President George Bush will approve the sale, worth $3 billion to $4 billion, before he departs from the White House on Jan. 20 or will leave it to his successor to decide.

Joseph Wu, Taiwan's quasi-ambassador in Washington, told the Reuters News Agency last week: "We hope that the U.S. administration will approve the requested sale as soon as possible. We believe that Taiwan's acquisition of additional F-16s ... will do much to enhance Taiwan's air defense."

Adm. Timothy Keating, who commands U.S. forces in the Pacific, had a different view. He told the Heritage Foundation in Washington that he saw "no pressing, compelling need at this moment for arms sales to Taiwan."

Another element in this equation is Congress. Last month, 14 senators led by Sens. Tim Johnson, D-S.D., and James Inhofe, R-Okla., wrote President Bush: "We believe that a freeze on foreign military sales to Taiwan violates the spirit of the Taiwan Relations Act. We have made attempts to clarify the status of these requests but to no avail."

The Taiwan Relations Act, adopted in 1979 when the U.S. switched diplomatic relations to China from Taiwan, requires the U.S. to "make available to Taiwan such defense articles and defense services in such quantity as may be necessary to enable Taiwan to maintain a sufficient self-defense capability."

A Chinese scholar visiting the U.S. asserted that an F-16 sale to Taiwan would violate the diplomatic communiques that supposedly define relations between Washington and Beijing. He repeated Beijing's opposition to such an arms sale but did not threaten dire consequences if it went through.

The first 150 F-16s, models A for the single seater and B for the two seater, were sold to Taiwan for $3 billion in 1992 during the first President George Bush's reelection campaign against Bill Clinton. They were approved by the president and Congress and provided jobs in his home state of Texas where they were assembled. Training at Luke AFB, where 14 of Taiwan's F-16s remain, was included.

The F-16s under consideration now are models C and D with improved navigation, advanced missiles and more powerful engines. They can attack in bad weather and at night and would pose a potential threat to the launch sites of 1,400 Chinese missiles aimed at Taiwan across the 120-mile-wide strait separating the island from the mainland.

Richard Halloran is a Honolulu-based journalist and former New York Times correspondent in Asia. His column appears weekly in Sunday's Focus section.