TAIPEI--A senior U.S. official will speak alongside Taiwanese President Tsai Ing-wen at an event in Taipei on Wednesday, just days after U.S. President Donald Trump signed a new law promoting exchanges between officials from the two sides that has drawn protests from Beijing.

The appearance by State Department official Alex Wong was to follow an announcement by Taiwan's defense minister that China's sole operating aircraft carrier, the Liaoning, had been spotting entering the Taiwan Strait separating the sides on Tuesday.

Yen Teh-fa told a legislative hearing that Taiwan's armed forces were monitoring the situation but declined to give further details. The 60,000-ton craft commissioned in 2012 had been conducting military operations in the East China Sea over recent days, Yen said.

The Liaoning has previously transited the heavily trafficked 160 kilometer-wide Taiwan Strait.

Wong's visit to Taiwan was expected to draw further criticism from China, which claims the self-ruled island as its own and has sought to isolate it diplomatically.

China has already lodged a protest over the new Taiwan Travel Law, saying it violates U.S. commitments not to restore formal exchanges severed when Washington switched recognition from Taipei to Beijing in 1979. Trump signed the law on Friday.

The deputy assistant secretary for East Asian affairs will speak at a dinner with the American Chamber of Commerce in Taipei on Wednesday, Taiwan's foreign ministry said.

Tsai's office has said she will be speaking at the same event.

On Tuesday, Chinese President Xi Jinping warned any attempt to separate any part of China from the nation would be "doomed to failure," a message implicitly directed at Taiwan and the United States. Xi said China would continue to seek peaceful unification with the island, from which it separated amid civil war in 1949, although China has refused to rule out using force to bring Taiwan under its control.

The new U.S. law allows unrestricted travel by U.S. officials to meet with members of Taiwan's government and for Taiwanese officials to visit the United States under "respectful conditions," during which they are allowed to meet with their counterparts, including those from the departments of state and defense.