The United States will act “without fear or hesitation” in Asia, including in the Taiwan Strait, Vice President Kamala Harris said Wednesday, addressing the American military in Japan, AFP reports.

Speaking a day after attending a state funeral for slain former Japanese Prime Minister Shinzo Abe, Harris accused Beijing of “disturbing behavior” in the East and South China seas and “provocations in the Taiwan Strait.”

“The US believes that peace and stability in the Taiwan Strait are important components of a free and open Indo-Pacific region,” she said, using Washington’s term for the Asia-Pacific region.

“We will continue to fly, swim and operate without fear or hesitation wherever international law allows,” she added.

Beijing claims both Taiwan and the narrow stretch of water that separates the island from mainland China, one of the world’s busiest shipping lanes.

Kamala Harris reaffirmed Washington’s longstanding position against any unilateral attempts by Beijing to seize Taiwan, while pledging to continue US support for the island’s defense.

President Joe Biden reaffirmed that commitment earlier this month. In an interview with CBS, Biden was asked whether “there will be Americans who will defend Taiwan in the event of a Chinese invasion.”

“Yes, if there was an unprecedented attack,” the US president replied.

China reacted strongly, condemning Washington’s “serious violation” of its promises to Beijing.

Washington “does not seek conflict with China,” Harris said, but “we expect Beijing to continue its aggressive behavior in an attempt to unilaterally undermine the status quo.”

In a speech aboard the USS Howard at the Yokosuka Naval Base near Tokyo, the US vice president also criticized Russia for “attempting to annex the territory of another sovereign state,” referring to Moscow’s vote in occupied areas of Ukraine.

Harris is due to fly out of Japan on Wednesday night for South Korea.