US lawmakers pressed Friday for a robust defense of Taiwan, voicing alarm over Pentagon plans to defund upgrades of the island's fighter jets as part of budget cuts.

Crossing party lines, members of the House Foreign Affairs Committee called for the United States to stand firm on protecting Taiwan and to ignore concerns by a rising China, which considers the self-governing democracy to be a province awaiting reunification.

The Air Force, as part of its 2015 budget request, ends funding for a program announced in 2011 in which the United States planned $5.85 billion in upgrades of Taiwan's fleet of F-16 jets.

"It just makes no sense to me whatsoever," said Representative Eliot Engel, the top member of the panel from President Barack Obama's Democratic Party.

"When it comes to Taiwan, there's this sort of undercurrent that we feel all the time where we bend over backwards to try not to upset the sensitivities of the Beijing regime. And frankly, it irks me," Engel said.

State Department official Kin Moy insisted that the Obama administration was fully committed to Taiwan's defense, pointing to its $12 billion in announcements of arms sales.

The Air Force has determined that the cutoff "will not have a significant impact on the Taiwan program, and that all funding can be covered in Taiwan's current letter of offer and acceptance," Moy said in response to lawmakers' questions.

Major General Jim Martin, the Air Force director of budget, told reporters earlier this month that the defunding of the upgrade program was among "very tough trade-offs" as the military put a priority instead on buying new equipment.

Moy called on Taiwan to find its own "innovative" ways to ensure defense funding.

Taiwan, however, has also been trimming its defense budget as President Ma Ying-jeou pursues a policy of reconciliation with Beijing. Taiwan's government was founded by Chinese nationalists who fled in 1949 after losing the mainland's civil war.

- Budget cuts in Taiwan, US, but not China -

Beijing has ramped up military spending over the past decade as its economy grows, last week unveiling a 12.2 percent increase for 2014.

While Beijing's declared defense budget remains a fraction of Washington's, many experts say that the mainland has increasingly ensured a decisive military advantage if it ever attacked Taiwan.

The Obama administration, announcing the plane upgrade in 2011, insisted that the move was a more modern way to provide for Taiwan's defense needs.

Critics charged that the administration was avoiding stronger Chinese criticism by not agreeing to Taiwan's request to buy 66 state-of-the-art F-16 C/D fighters rather than retrofitting the existing F-16 A/B fleet.

Representative Ed Royce, the Republican chairman of the House Foreign Affairs Committee, said that ending funding for the retrofit was "discouraging."

"I would suggest the sale of new F-16s would be an easy solution to this," he said.

In 1979, the United States switched recognition from Taipei to Beijing in a seismic diplomatic shift.

Congress at the same time approved the Taiwan Relations Act, which requires the United States to ensure Taiwan's self-defense.

Congress has remained a stronghold of support for Taiwan, which takes pains to woo lawmakers from both parties.

The Obama administration has pledged to "pivot" the US focus to Asia on a wide range of foreign policy issues.

At the same time, the US Army plans to scale back to its lowest level since before World War II with the end of wars in Afghanistan and Iraq.