Beijing urged Washington to avoid actions that could undermine stability in the Taiwan Strait and to respect China's territorial integrity, the Chinese Foreign Ministry said on Monday.
"We must stress that observing territorial integrity and sovereignty is the crucial issue in the Chinese-US relations; we urge Washington to act in accordance with the provisions of the three Chinese-US joint communiques, and not to undermine bilateral relations, peace and stability on both sides of the Taiwan Strait," Hua Chunying, the ministry's spokeswoman, said at a briefing.
On Saturday, Channel News Asia said that two US warships passed through the Taiwan Strait in a move which was reportedly likely to be viewed by Taipei as a demonstration of US support for the self-ruled island.
China's concerns over US activity in Taiwan emerged amid heightened Beijing-Washington trade tensions and the Taiwan Travel Act, signed by US President Donald Trump, which now allows US officials to travel to the island and meet their Taiwanese counterparts.
The United States has not recognized Taiwan as an independent state. The US government declared it would end all political ties with Taiwan after the joint 1979 communique, but continued to maintain economic and cultural relations via the American Institute in Taiwan.