U.S. Vice President Kamala Harris condemned China's "disturbing" actions in an address to U.S. sailors based in Japan, Reuters reported.
"China is undermining key elements of the international rules-based order," Harris said during a visit to the world's largest overseas U.S. Navy base in Yokosuka, near Tokyo.
"China has flexed its military and economic might to coerce and intimidate its neighbours. And we have witnessed disturbing behaviour in the East China Sea and in the South China Sea, and most recently, provocations across the Taiwan Strait," she added.
Earlier, U.S. President Joe Biden, in an interview aired Sept. 18, pledged to protect Taiwan from an "unprecedented attack."
Harris said U.S. troops would continue to operate in the region fearlessly and bravely.
We will continue to oppose any unilateral change to the status quo," she said. "And we will continue to support Taiwan's self-defence, consistent with our long-standing policy. Taiwan is a vibrant democracy that contributes to the global good - from technology to health, and beyond, and the United States will continue to deepen our unofficial ties."
The base where Harris spoke is home to 24,000 military and civilian personnel who could be deployed in the event of regional conflict. It is also home to the aircraft carrier USS Ronald Reagan, which is now in South Korea to participate in a joint exercise aimed at deterring North Korea.
Biden is expected to have his first face-to-face meeting as president with Chinese President Xi Jinping during the November G-20 meeting in Indonesia.