The US would come to Taiwan’s defence and has a commitment to defend the island China claims as its own, US President Joe Biden said on Thursday, though the White House said later there was no change in policy towards the island.

“Yes, we have a commitment to do that,” Biden said at a CNN town hall when asked if the US would come to the defence of Taiwan, which has complained of mounting military and political pressure from Beijing to accept Chinese sovereignty.

While Washington is required by law to provide Taiwan with the means to defend itself, it has long followed a policy of “strategic ambiguity” on whether it would intervene militarily to protect Taiwan in the event of a Chinese attack.

In August, a Biden administration official said US policy on Taiwan had not changed after the President appeared then to suggest the US would defend the island if it were attacked.

A White House spokesperson said Biden was not announcing any change in US policy at the town hall and “there is no change in our policy”, but declined further comment when asked if Biden misspoke.

“The US defence relationship with Taiwan is guided by the Taiwan Relations Act. We will uphold our commitment under the Act, we will continue to support Taiwan's self-defence, and we will continue to oppose any unilateral changes to the status quo,” the spokesperson said.

China expressed its displeasure anyway, with a foreign ministry spokesman saying Beijing has no room for concessions on its core interests. China urges the US “not to send the wrong signals to the forces of Taiwan independence, to avoid seriously harming Sino-US ties and peace and stability in the Taiwan Strait”, spokesman Wang Wenbin said.

Taiwan’s presidential office said its position remained the same, which is that it will neither give in to pressure nor “rashly advance” when it gets support.

Taiwan will show a firm determination to defend itself, presidential office spokesperson Xavier Chang said in a statement, adding that the Biden administration's continued concrete actions show its “rock-solid” support for Taiwan.

Bonnie Glaser, a Taiwan expert at the German Marshall Fund of the US, called Biden’s remark a “gaffe” and said it was “patently not true” that Washington has a commitment to defend Taiwan.

“Some are suggesting a deliberate effort to send unclear signals, but in my view, that makes no sense. A confused US policy weakens deterrence,” she said, noting that Biden’s Asia policy czar, Kurt Campbell, had rejected “strategic clarity” over Taiwan.