WASHINGTON — Two key GOP senators are pressing U.S. President Donald Trump to share Lockheed Martin’s F-35 or F-16V fighter jet to upgrade Taiwan’s aging air power and deter China.

Sens. John Cornyn and Jim Inhofe sent the letter to Trump on Monday, days after Taiwan defense officials confirmed their long-standing interest in the F-35. Cornyn, of Texas, is the Senate’s No. 2 Republican, and Inhofe, of Oklahoma, is the Senate Armed Services Committee’s No. 2 Republican.

The F-16V — billed as the most advanced fourth-generation fighter — would be a cost-effective alternative to the fifth-generation F-35, the letter argues. The lawmakers also said it would address the “quantitative and qualitative challenges” of Taiwan’s air defense fleet.

Of 144 F-16s Taiwan bought from the U.S. in 1993, 15 are in the U.S. for training purposes and 24 more will be offline for upgrades on a rolling basis through 2023. That means Taiwan is likely able to field only 65 F-16s at any given time in defense of the island — “not enough to maintain a credible defense,” the letter reads.

“If Taiwan’s air defense fleet is allowed to degenerate in number and quality, I am concerned that it would be destabilizing and would encourage Chinese aggression to ensue,” the letter reads. “Additionally, I am concerned that Taiwan’s military weakness and the inability to mount a credible air force would place an undue burden on forward-deployed U.S. forces in North East Asia.”

Those upgrades include fitting the F-16 with the active electronically scanned Northrop Grumman AN/APG-83 Scalable Agile Beam Radar, a new mission computer and an electronic warfare suite.

Taiwan is reportedly interested in the F-35B short-takeoff-and-vertical-landing version, through which Taiwan would aim to maintain air power if China attacked its runways in a first strike.

“The survivability of the F-35B and modern long-range sensors could help Taiwan intercept Chinese missiles, promoting deterrence well into the next decade,” the letter reads. “The F-35B would not only provide a modern fifth-generation fighter, but would also bolster their capabilities in next-generation warfare.”

Earlier this month, Chinese President Xi Jinping issued a warning to Taiwan, which China views as a breakaway province. However, Washington provides arms to Taipei under the 1979 Taiwan Relations Act, and Trump days ago signed a bill to make it easier for the U.S. and Taiwan to exchange official visits.

In June, China demanded Washington reverse its decision to sell Taiwan $1.42 billion worth of arms, saying it contradicted a “consensus” that Xi reached with Trump during talks in Florida last year.

Inhofe in February completed a congressional trip to the Asia-Pacific region, which included a visit to Taiwan.