"The president was not announcing any change in our policy and there is no change in our policy," a White House spokesperson said.

The White House said it was still guided by the 1979 Taiwan Relations Act, in which Congress required the United States to provide the island weapons for its own defense but was ambiguous on whether the United States would intervene militarily.

"We will uphold our commitment under the act to support Taiwan's self-defense, and we will continue to oppose any unilateral changes in the status quo," the spokesperson said.

Biden, asked at a CNN televised forum Thursday night if the United States would come to Taiwan's defense if China invaded, replied, "Yes."

"We have a commitment to that," he said.

The Taiwan Relations Act was passed when the United States switched recognition from Taipei to Beijing and committed Washington to maintain de facto diplomatic relations with Taiwan.