China firmly opposed the recent visit of US congressmen to Taiwan, and has lodged solemn representations with the US, said spokesperson Wang Wenbin on Monday.
Three US senators arrived on Sunday in Taiwan in a military plane and met Taiwan leader Tsai Ing-wen.
The action has seriously violated the one-China principle and the three China-US joint communiques, Wang stressed.
Wang urged the US to immediately stop any form of official exchange with Taiwan.
"They should stop sending the wrong signals to 'Taiwan independence' secessionist forces, and seriously damage peace and stability across the Taiwan Straits as well as China-US relations."