A United States Navy warship and a Canadian frigate have sailed through the Taiwan Strait amid heightened military tensions between Beijing and Taipei.
China condemned the mission, saying its forces "warned" the ships.
In recent years, US warships, and on occasion those from allied nations such as Britain and Canada, have routinely sailed through the strait, drawing the ire of China, which claims Taiwan over the objections of the island's democratically elected government.
In a statement, the US Navy said its Arleigh Burke-class guided-missile destroyer Higgins and the Royal Canadian Navy's Halifax-class frigate Vancouver conducted the transit through a corridor in the strait beyond the territorial sea of any coastal state.
"Co-operation like this represents the centrepiece of our approach to a secure and prosperous region," the statement said.
Canada's Defence Minister Anita Anand said her country was deeply committed to upholding global stability and prosperity in the Indo-Pacific region.
"Today's routine Taiwan Strait transit demonstrates our commitment to a free, open and inclusive Indo-Pacific," she said in a statement.
The Eastern Theatre Command of China's People's Liberation Army said its forces monitored the ships and "warned them".
"Theatre forces are always on high alert, resolutely counter all threats and provocations, and resolutely defend national sovereignty and territorial integrity," it said in a statement.
Taiwan's defence ministry said the ships sailed north through the waterway and that its forces observed the mission but "the situation was as normal".
It was the second transit of the strait in a month by a US Navy ship, and the second joint transit by the US and Canada since October.
A visit to Taiwan by US House of Representatives Speaker Nancy Pelosi in early August enraged China, which regards the island as its territory.
China subsequently launched military drills near the island, which have continued on a much-reduced scale.
The narrow Taiwan Strait has been a frequent source of military tension since the defeated Republic of China government fled to Taiwan in 1949 after losing a civil war with the communists, who established the People's Republic of China.