The US president said “yes” when asked during an interview broadcast on Sunday on CBS News’s 60 Minutes whether “US forces, US men and women, would defend Taiwan in the event of a Chinese invasion”.
CBS News reported the White House said after the interview that US policy has not changed.
That policy says Washington wants to see Taiwan’s status resolved peacefully but does not say whether US forces might be sent in response to a Chinese attack.
Tensions have risen rising following efforts by Chinese President Xi Jinping’s government to intimidate Taiwan by firing missiles into the nearby sea and flying fighter jets close by amid visits to Taipei by political figures including US House speaker Nancy Pelosi.
Taiwan’s foreign ministry on Monday expressed “sincere gratitude” to Mr Biden for “affirming the US government’s rock-solid promise of security to Taiwan”.
Taiwan will “resist authoritarian expansion and aggression” and “deepen the close security partnership” with Washington and other governments “with similar thinking” to protect regional stability, the statement said.
Washington is obligated by federal law to see that Taiwan has the means to defend itself but does not say whether US forces would be sent.
The United States has no formal relations with the island but maintains informal diplomatic ties.
Taiwan and China split in 1949 after a civil war that ended with the Communist Party in control of the mainland. The two governments say they are one country but dispute which is entitled to be the national leader.
Beijing criticises official foreign contact with Taiwan’s elected government as encouragement to make its de facto independence permanent, a step the mainland says would lead to war.
Washington says it does not support formal independence for Taiwan, a stance Mr Biden repeated in the interview broadcast on Sunday.
“Taiwan makes their own judgements about their independence,” the president said. “We’re not encouraging their being independent.”
In May, Mr Biden said “yes” when asked at a news conference in Tokyo whether he was willing to get involved militarily to defend Taiwan if China invaded.