The US has admitted that it has approximately 500 military personnel stationed in Taiwan breaking previous pledges to not post soldiers on the contested island.

Retired US Navy Rear Admiral Mark Montgomery made the admission of a US military presence on Taiwan during testimony before lawmakers on May 15 – the first official confirmation of long-time suspicions that the US has a military footprint in Taiwan.

The soldiers are provocative as China considers Taiwan to be its sovereign territory, so any US military presence there can be viewed in Beijing as a foreign occupying force.

“This is extremely provocative,” said political commentator and bne IntelliNews columnist Arnaud Bertrand. “This is despite the US famously committing in its 1978 normalisation agreement with the PRC – the agreement that established diplomatic relations with China – [not to] have any US military forces in Taiwan. An agreement the US apparently abided by until the Biden administration, which acknowledged they had 41 personnel stationed on the island. And it's now been increased to 500...”

“Why is it provocative? Not only because the US formally committed not to do that, but because of course from China's standpoint Taiwan is a Chinese province, so these troops are effectively a de-facto invasion of their sovereign territory by the US,” Bertrand added.

Tensions between China and the US are at a post-Cold War high since US President Donald Trump took over the presidency in January. The admission of US boots on the ground in Taiwan marks a significant shift towards more open support for the island, challenging Beijing’s long-standing opposition to foreign military cooperation with Taipei, analysts said following a recent congressional disclosure.

Fears of a military conflict between the US and China have been mounting: in remarks earlier this year, US Vice President JD Vance said that the US should pull out of all foreign contests, except with China, where America needs to “prepare for war.”

According to Montgomery, the American forces are involved in training Taiwan’s military to become a credible “counter-intervention force” to a possible Chinese invasion.

“If we’re going to give them billions of dollars in assistance, sell them tens of billions of dollars’ worth of US gear, it makes sense that we’d be over there training and working,” Montgomery said.

Beijing is likely to take the news badly, partly because Washington itself acknowledges Taiwan is sovereign Chinese territory. Washington officially does not recognise Taiwan as an independent state and only as a de facto democratic country. The US has tacitly signed off on Beijing’s "One China" policy that acknowledges Beijing's position that Taiwan is part of China. None of the major Western powers have an embassy in Taipei or formal diplomatic relations with the breakaway island.

“As such even from the American government's own stated position, these 500 troops are deployed within what they acknowledge as sovereign Chinese territory,” says Bertrand.

The figure sharply exceeds the previously reported 41 personnel noted in a US congressional report one year ago. The admission is part of what China calls the US' "salami slicing" strategy: a series of small moves which in and of themselves do not justify war but which taken together fundamentally change the status quo, says Bertrand.

Taiwanese experts counter that the deployed troops are training personnel, indicating a sustained “military engagement” rather than “combat deployment.”

Mainland Chinese state broadcaster CCTV condemned the force in a rare commentary on Montgomery’s remarks days after the hearing.

The development has generated mixed reactions amongst other observers. Some analysts have downplayed the strategic impact of the number, while others argue that the disclosure puts China in a difficult position, forcing a response without provoking outright conflict.

“This is an open test of Beijing’s red lines,” Taiwan-based analyst Enoch Wong told the South China Morning Post. “The US is no longer hiding its presence. It is now transparent, and that transparency is strategic.”

The Pentagon has not publicly confirmed Montgomery’s comments, and there has been no formal response from Taiwan’s Ministry of National Defence. However, the open presence of US forces in Taiwan comes as US arms sales and military cooperation with Taiwan increases under the Taiwan Enhanced Resilience Act, which includes $10bn in military aid over five years.

China’s defence ministry has repeatedly stated that it opposes “external interference” in Taiwan-related matters and reserves the right to take “all necessary measures” to protect its sovereignty.

The US maintains a policy of strategic ambiguity regarding Taiwan, formally recognising Beijing but supporting Taipei’s self-defence capabilities under the Taiwan Relations Act.