A Canadian frigate was passing through the Taiwan Strait on Tuesday, Taiwanese and Canadian authorities said, in the latest of a string of such voyages likely to provoke Beijing.
Taiwan's defence ministry said it was closely monitoring as the Canadian warship sailed through the narrow waterway separating the island and the Chinese mainland in a "freedom of navigation" operation.
China views any passing through the strait as a breach of its sovereignty -- while the US and many other nations see the route as international space.
"The HMCS Ottawa's current deployment is consistent with past Royal Canadian Navy practice and international law," Canada's de facto embassy in Taipei said in a statement.
It added that sailing through the strait is "the most practical route" between South Korea's Pyeongtaek and the Thai capital Bangkok.
Taiwan has been run as a de facto independent nation for the last seven decades but Beijing sees as part of its territory awaiting reunification, by force if necessary.
In June, a Canadian frigate and its supporting vessel also sailed through the Taiwan Strait.
Relations between China and Canada have deteriorated since December when police in Vancouver detained Huawei chief financial officer Meng Wanzhou on a US arrest warrant.
Days after her arrest, China detained two Canadians -- a former diplomat and a businessman -- and accused them of spying in what is seen as a tit-for-tat move.
China has also blocked Canadian agricultural shipments worth billions of dollars.
Taiwan had called the June voyage a "freedom of navigation" operation, but Canada's military said the journey was "not related to making any statement".
Last month, a US military plane flew over the Taiwan Strait, just days after one of its navy ships sailed through the waters and the latest arms sale between Taipei and Washington.
Beijing threatened to sanction US firms involved in the sale of the fighter jets, at a time when relations are already strained by a punitive trade war.