Washington is Taipei's biggest arms supplier and a key deterrent to a potential Chinese attack, but Trump's remarks on Taiwan have raised doubts about his willingness to defend the democratic island.

Beijing claims Taiwan is part of its territory and has threatened to use force to bring it under its control.

"This marks the first time the new Trump administration has announced an arms sale to Taiwan," the foreign ministry said, after the US State Department approved the package.

Taiwan requested "non-standard components, spare and repair parts, consumables and accessories, and repair and return support for F-16, C-130, and Indigenous Defense Fighter (IDF) aircraft," a statement posted by the US Defense Security Cooperation Agency said.

China's foreign ministry said it "firmly opposed" Washington's approval of the sale, which comes about two weeks after Trump met with Chinese President Xi Jinping in South Korea.

Taiwan has its own defence industry, but the island's military would be massively outgunned in a conflict with China and remains heavily reliant on US weapons for self-defence.

Taiwan's defence ministry said the sale will help maintain "combat readiness" and "enhance defensive resilience" against China.

China deploys military aircraft and warships around Taiwan on a near-daily basis, which analysts describe as "grey-zone" operations -- coercive tactics that fall short of an act of war.

- 'Strategic ambiguity' -

While the United States is legally bound to provide arms to Taiwan, Washington has long maintained "strategic ambiguity" when it comes to whether it would deploy its military to defend the island from a Chinese attack.

Taiwanese President Lai Ching-te has been at pains to find favour with Trump, vowing to raise defence spending to more than three percent of GDP next year and five percent by 2030.

Lai has also pledged to boost investment in the United States as his government tries to reduce Trump's 20-percent tariff on Taiwanese exports.

But his government's plans for a special defence budget of up to NT$1 trillion (US$32 billion), which will include US arms, could be derailed by the main opposition Kuomintang party (KMT), which controls parliament with the help of the Taiwan People's Party.

Opposition lawmakers have expressed frustration over the backlog of US deliveries to Taiwan, worth billions of dollars, caused by Covid-19 supply chain disruptions and US weapons shipments to Ukraine and Israel.

The Beijing-friendly KMT's new chairperson Cheng Li-wun told AFP recently that Taiwan cannot afford to increase defence spending above three percent of GDP, saying "Taiwan isn't an ATM".

The US arms sale is the first since December 2024 under former president Joe Biden.

It comes as Beijing and Tokyo row over remarks by Japan's new hawkish premier about Taiwan.

Prime Minister Sanae Takaichi told parliament last week that armed attacks on Taiwan could warrant sending troops to support the island under "collective self-defence".

Beijing has slammed Takaichi's remarks, with its foreign ministry on Thursday saying it "will by no means tolerate" it.