U.S. President Joe Biden said on Tuesday that he has spoken to Chinese President Xi Jinping about Taiwan and they agreed to abide by the Taiwan agreement as tensions grow between Taipei and Beijing.

"I've spoken with Xi about Taiwan. We agree ... we'll abide by the Taiwan agreement," he said. "We made it clear that I don't think he should be doing anything other than abiding by the agreement."

Biden appeared to be referring to Washington's long-standing "one-China policy" under which it officially recognizes Beijing rather than Taipei, and the Taiwan Relations Act, which makes clear that the U.S. decision to establish diplomatic ties with Beijing instead of Taiwan rests upon the expectation that the future of Taiwan will be determined by peaceful means.