The Chinese military on Sunday condemned the United States and Canada for each sending a warship through the Taiwan Strait last week, saying they were threatening peace and stability in the region.
China claims democratically-ruled Taiwan as its own territory and has mounted repeated air force missions into Taiwan's air defense identification zone (ADIZ) over the past year or more, provoking anger in Taipei.
China sent around 150 aircraft into the zone over a four-day period beginning on October 1 in a further heightening of tension between Beijing and Taipei that has sparked concern internationally.
The US military said the Arleigh Burke-class guided-missile destroyer USS Dewey sailed through the narrow waterway that separates Taiwan from its giant neighbor China along with the Canadian frigate HMCS Winnipeg on Thursday and Friday.
"Dewey's and Winnipeg's transit through the Taiwan Strait demonstrates the commitment of the United States and our allies and partners to a free and open Indo-Pacific," it added.
China's People's Liberation Army's Eastern Theatre Command said its forces monitored the ships and "stood guard" throughout their passage.
"The United States and Canada colluded to provoke and stir up trouble... seriously jeopardizing peace and stability of the Taiwan Strait," it said.
"Taiwan is part of Chinese territory. Theater forces always maintain a high level of alert and resolutely counter all threats and provocations."
American Navy ships have been transiting the strait roughly monthly, to the anger of Beijing, which has accused Washington of stoking regional tensions. US allies occasionally also send ships through the strait, including a British warship.
While tensions across the Taiwan Strait have risen, there has been no shooting and Chinese aircraft have not entered Taiwanese air space, concentrating their activity in the southwestern part of the ADIZ.
While including Taiwanese territorial air space, the ADIZ encompasses a broader area that Taiwan monitors and patrols that acts to give it more time to respond to any threats.
Taiwan's defense ministry said on Sunday that three Chinese aircraft - two J-16 fighters and an anti-submarine aircraft - flew into the ADIZ again.