The US urged "restraint" from both sides of the Taiwan Strait amid speculation over mainland China's military response to Taiwanese leader William Lai Ching-te's upcoming speech to mark the self-governing island's Double Tenth Day.

A senior official of US President Joe Biden's administration said Beijing could use Lai's speech on Thursday as a "pretext" for taking military action in the Taiwan Strait.

"We see no justification for a routine annual celebration to be used in this manner," the official said in a background call with the press on Wednesday.

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"A cause of action like this against Taiwan and in the cross-strait context, in our view, undermines cross-strait peace and stability.

"We'll be calling on both sides to aggregate restraint and consistent with long-standing norms," the official added.

Lai, who was inaugurated in May after winning election earlier this year, will deliver his first speech on Thursday celebrating the Double Tenth Day, which marks the founding of the Republic of China.

The Republic of China was founded in mainland China in 1912, following the fall of the Qing dynasty. Taiwan has used the Republic of China as its official name since the Kuomintang fled to the island in 1949 after being defeated by the Communist Party in China's civil war.

Lai's speech is expected to call for "national unity" and strengthening the island's international status, according to Taiwan's Central News Agency.

The Biden official said Taiwan briefed its "diplomatic partners" about the speech.

As Beijing regards Lai as a "stubborn separatist", the speech is expected to infuriate mainland authorities.

Beijing sees Taiwan as part of China to be reunited by force if necessary. Three days after Lai's inauguration, Beijing launched two days of intensive drills in the strait.

Most countries, including the United States, do not recognise Taiwan as an independent state, but Washington is opposed to any attempt to take the self-governed island by force and is committed to supplying it with weapons.

A Taiwanese coastguard vessel on patrol near the maritime boundary between Taiwan and mainland China in May. Photo: EPA-EFE alt=A Taiwanese coastguard vessel on patrol near the maritime boundary between Taiwan and mainland China in May. Photo: EPA-EFE>

On Wednesday, the mainland's Taiwan Affairs Office lashed out at Lai for "escalating hostility" in response to his claim that "the Republic of China may very well be the motherland of people [aged] above 75 in the People's Republic of China".

The Biden official's statement came after Reuters, quoting intelligence sources from Taiwan, reported that the mainland could use Lai's remarks as a reason to launch military drills around the island this week.

China has shown that it possesses enhanced military "capabilities" in the Indo-Pacific region through its drills, the official added: "Not just in the cross-strait context but also in the South China Sea and the East China Sea, the number of assets that China has, the exercises it is undertaking, the extent of its operations, have increased over time."

The US and China are fierce rivals in the region. Beijing conducted a military drill in the contested South China Sea on its national day on October 1, following a joint exercise by navies of the US, the Philippines, Japan, Australia and New Zealand.

The Biden official did not answer a question on whether Washington thought Beijing would weigh its military options based on the close timing between Lai's October 10 speech and the US presidential election set for November 5.

Meanwhile, both US presidential candidates have been grilled about Taiwan recently while on the campaign trail.

In an interview with the American news programme 60 Minutes on Monday, Democratic nominee Kamala Harris dodged a question about whether the US would use its armed forces to defend Taiwan.

The incumbent vice-president said she would not "get into hypotheticals" while repeating the official US stance of supporting a "one-China policy".

"We need to make sure that we maintain our one-China policy, but that includes supporting Taiwan's ability to defend itself ... we need to make sure we have open lines of communication with China, in particular military-to-military," Harris said.

In response to Harris' comments, the campaign of her Republican rival for the White House, former president Donald Trump, said in a post on X (formerly Twitter) that his opponent was "completely clueless" and "dangerous".

When asked the same question in July, Trump replied that he would ask Taiwan to pay the US for its defence.

China has repeatedly warned the US that Taiwan is the "first red line" not to be crossed in Sino-American relations amid the Biden's administration continuing arms sales to the island.

This article originally appeared in the South China Morning Post (SCMP), the most authoritative voice reporting on China and Asia for more than a century. For more SCMP stories, please explore the SCMP app or visit the SCMP's Facebook and Twitter pages. Copyright © 2024 South China Morning Post Publishers Ltd. All rights reserved.

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