President Joe Biden said the US would defend Taiwan if China attacked, in an apparent departure from a long-held US foreign policy position.
But a White House spokesman later told some US media outlets that his remarks did not signify a change in policy.
The US has a law which requires it to help Taiwan defend itself.
But it pursues a policy of “strategic ambiguity,” where it is deliberately vague about what it would actually do if China were to attack Taiwan.
China has yet to respond to Mr. Biden’s comments.
A White House spokesperson later appeared to walk back Mr. Biden’s comments, telling US media outlets that the US was “not announcing any change in our policy and there is no change in our policy”.
This is not the first time this has happened. In August, Mr. Biden appeared to suggest the same stance on Taiwan in an interview. The White House had also said then that US policy on Taiwan had not changed.
The US has no official diplomatic ties with Taiwan but sells arms to it as part of its Taiwan Relations Act, which states that the US must provide the island with the means to defend itself.
It has formal ties with China and diplomatically acknowledges China’s position that there is only one Chinese government.