US President Joe Biden said US soldiers would defend Taiwan if China "intervened"; his most unequivocal remark on the matter to date, with statements aimed at enraging Beijing.

On CBS' 60 Minutes on Sunday, when asked whether the US military would protect the "democratically governed island claimed by China," he said, "Yes, if there was an unprecedented attack."

Biden again answered, "Yes," when asked if he meant that, unlike in Ukraine, US forces would protect Taiwan in the event of a Chinese "invasion".

The interview was simply the latest instance in which Biden appeared to go beyond long-standing official US policy on Taiwan, but his declaration about committing US troops to "defend" the island was clearer than prior ones.

The US has long maintained a policy of "strategic ambiguity", refusing to say whether it would respond militarily to an alleged attack on Taiwan. Asked to comment, a White House spokesperson claimed that US policy toward Taiwan had not changed, although the "defense" part was made clear by Biden.

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"The President has said this before, including in Tokyo earlier this year. He also made clear then that our Taiwan policy hasn't changed. That remains true," the Spokesperson said.

Taiwan's Foreign Ministry expressed thanks to Biden for his reaffirming the "US government's rock-solid security commitment to Taiwan."

It will continue to develop its self-defense capabilities and extend its security collaboration with the US, according to a statement.

Biden was asked in May if he was willing to get involved militarily to defend Taiwan and replied: "Yes ... That's the commitment we made."

In the 60 Minutes interview, Biden still claimed that the US does not support Taiwanese independence and is committed to a "One-China" policy whereby Washington recognizes Beijing rather than Taipei.

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US eyes on Taiwan 

Biden's words are expected to resonate across Beijing, which was already enraged by US House Speaker Nancy Pelosi's visit to Taiwan in August followed by other US officials' visits to the island. 

This visit prompted China to conduct its largest-ever military drills surrounding Taiwan, and China has condemned US senators' efforts to approve legislation that would strengthen US military assistance for Taiwan.

Xi warned Biden in a phone call in July not to play with fire over Taiwan, stating that "those who play with fire will perish by it."