President Joe Biden of the United States warned on Monday that he would be prepared to use force to defend Taiwan, evoking praise from the democratic, self-ruled island but fierce rebuke from China.

When asked if the US would protect Taiwan if it was invaded during a joint press conference with Japanese Prime Minister Fumio Kishida, Biden said, “Yes.”

“That’s the commitment we made,” Biden said. “We agree with the ‘one China’ policy. We signed on to it. All the attendant agreements [were] made from there. But the idea that that can be taken by force, just taken by force. It’s just not it’s just not appropriate.”

Taiwan’s foreign ministry hailed Biden for pledging the United States’ support in the event that Beijing attacked the island. According to Reuters, China’s foreign ministry stated that the US should not back Taiwan’s independence, and that Beijing has no space for compromise or concessions on issues of sovereignty and territorial integrity.

Taiwan and the Chinese mainland China is divided by the Taiwan Strait, which is only around 100 miles (160 kilometers) wide at its narrowest point. China considers Taiwan to be part of its territory and has been pressuring the democratic island to accept its control.

Biden’s remarks appeared to defy Washington’s long-standing policy of “strategic ambiguity” on Taiwan, in which the White House has been deliberately ambiguous about whether it would intervene on the island’s behalf if China attacked. The goal of this strategy had been to keep the mainland from engaging in military action without committing the US to war.

According to a White House official, Biden’s remarks do not represent a policy shift.

The United States officially accepts China’s claim that there is only one Chinese government under the “one China” policy, which is a cornerstone of diplomatic ties between Washington and Beijing.

The United States, however, maintains a strong unofficial connection with Taiwan, and Washington transfers military weapons to the island in compliance with the Taiwan Relations Act of 1979. This legislation does not force the United States to intervene militarily to defend Taiwan if China invades, but it does make it a policy to guarantee the island has the resources to defend itself and to discourage Beijing from unilaterally uniting the island.

China has increased its military provocations against Taiwan in recent years, ostensibly to terrify what it considers a wayward colony into accepting Beijing’s demands for unification with the mainland.

Taiwan, as seen through the prism of Russia’s onslaught in Ukraine, was mentioned multiple times during Biden’s news conference.

Japan’s leader stated that the two nations’ positions on Taiwan remain unaltered, emphasizing the “importance of peace and stability in the Taiwan Straits, which is a vital ingredient for the peace and prosperity of worldwide communities.”

One political expert identified the hostile relationship between the United States and China over Taiwan as the greatest danger for Asia in 2022 at the start of the year.