As President Joe Biden continued his six-day trip to Asia, he made headlines when he said the United States military would intervene in the ongoing tensions between China and Taiwan should they escalate. President Biden was asked about the subject during a Monday news conference with Japanese Prime Minister Fumio Kishida.

“We support the ‘One China’ policy, we support all that we’ve done in the past, but that does not mean that China has the jurisdiction to go in and use force to take over Taiwan,” Biden said. “So we stand firmly with Japan and with other nations to not let that happen.”

Biden said the burden to protect Taiwan is “even stronger’ after Russia’s invasion of Ukraine. The U.S. has not directly gotten involved in Ukraine, and Biden said Monday he doesn’t see that happening in Taiwan.

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“My expectation is it will not happen, it will not be attempted,” Biden said of a potential Chinese invasion of Taiwan. “A lot of it depends upon just how strong the world makes clear that that kind of action is going to result in long term disapprobation by the rest of the community.”

Biden’s comments represented one of the most forceful presidential statements in support of a self-governing Taiwan in decades. In his response, a spokesperson for China’s Foreign Ministry said the country “expressed strong dissatisfaction and resolute opposition to the U.S. remarks.”

“We urge the U.S. side to… be cautious with its words and actions on the Taiwan issue, and not send any wrong signals to the separatist forces of Taiwan independence, so as to avoid serious damage to the situation in the Taiwan Strait and China-U.S. relations,” Wang Wenbin said. “China will take firm action to safeguard its sovereignty and security interests, and we will do what we say.”

The U.S. traditionally has avoided making such an explicit security guarantee to Taiwan, instead maintaining a policy of “strategic ambiguity” about how far it would be willing to go if China invaded. The 1979 Taiwan Relations Act only requires the U.S. to ensure Taiwan has the resources to defend itself and to prevent any unilateral change of status in Taiwan by Beijing.

A White House official said Biden’s comments on a potential military intervention between China and Taiwan did not reflect a policy shift.

The Associated Press contributed to the report.