The US does not maintain official diplomatic relations with Taiwan, but is required by the Taiwan Relations Act to support the self-governed island’s efforts to defend itself, including through arms sales. China regards Taiwan as a renegade province, destined for eventual reunification with the mainland, by force if necessary.

The Taiwan Relations Act does not, however, include a commitment to intervene militarily if China seeks to annex Taiwan by force. The US has for decades followed a policy of “strategic ambiguity”, in which it does not indicate whether it would take military action in Taiwan’s defence.

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China urges US President Joe Biden to act cautiously over Taiwan, warns ‘no room for compromise’

China urges US President Joe Biden to act cautiously over Taiwan, warns ‘no room for compromise’

Psaki said that the US would continue to abide by the principles of the act, reiterating one of its clauses that Washington “would regard any effort to determine the future of Taiwan by other than peaceful means a threat to the peace and security of the Western Pacific and of grave concern to the United States”.

“The president was not announcing any change in our policy, nor has he made a decision to change our policy,” Psaki said.

Psaki dodged a question about whether Biden had misspoken or if he was signalling a hardening of his administration’s position on Taiwan.

Earlier on Friday, Defence Secretary Lloyd Austin said that China’s ambitions and actions posed “challenges to the rules-based international order”, but stressed that the US remained committed to a “One China” policy, which allows Washington to acknowledge that Beijing considers Taiwan to be a part of China.

Biden sparks confusion with commitment to Taiwan’s defence if Beijing attacks

“Nobody wants to see cross-strait issues come to blows, and certainly not President Biden,” said Austin, who was in Brussels for a Nato meeting. “And there’s no reason that it should.”

Some supporters of a stronger, more explicit US commitment to Taiwan’s defence have pounced on Biden’s Thursday remarks as a signal that his administration was abandoning strategic ambiguity. That strategy is intended to dissuade Taipei from unilaterally declaring independence while discouraging Beijing from seeking to annex the island by force.

“Strategic ambiguity no longer serves the national interest,” Representative Mike Gallagher, a Wisconsin Republican, said in a statement. “It is clear that President Biden agrees.”

Gallagher added: “It is time to move past academic debates over the nature of our commitment to Taiwan and get down to the hard work of defending it against the Chinese invasion that looks increasingly likely.”

But as US officials on Friday sought to walk back Biden’s comments, others criticised what they viewed as “mixed messages” from the administration.

“Words are important, and we can’t be careless in how we talk about an issue that is so vital to US interests and the security of the Indo-Pacific,” said Senator James Risch of Idaho, the lead Republican on the Senate Foreign Relations Committee.

“We must act decisively on our commitments under the Taiwan Relations Act that bolster deterrence in the Indo-Pacific,” he continued.

Nominee for US ambassador to China takes tough line on Beijing, cites need to support Taiwan

“That means we must get asymmetric capabilities to Taiwan more quickly, increase training and exchanges that demonstrate readiness, sustain our own capacity to resist force and coercion in the Western Pacific and not abandon long-held US nuclear declaratory policy that has served us well for decades.”

The sharpest response to Biden’s comments came from Beijing, which chastised the US for sending the “wrong signals to the ‘Taiwan independence’ separatist forces”.

“No one should underestimate the resolve, the will and the ability of the Chinese people to defend their national sovereignty and territorial integrity,” foreign ministry spokesman Wang Wenbin said on Friday.