Two US warships are passing through the Taiwan Strait, the US Navy has announced.
It is the first such operation to take place since tensions between Taiwan and China increased following a visit by US House Speaker Nancy Pelosi to Taiwan earlier this month.
China reacted by holding large-scale military drills in the area.
The US and other Western navies have routinely sailed through the strait in recent years.
Washington says the two guided-missile cruisers - the USS Antietam and the USS Chancellorsville - are demonstrating freedom of navigation through international waters.
Beijing views such actions as provocative and maintains that the island of Taiwan is an integral part of Chinese territory.
On Sunday, its military said it was monitoring the two vessels' progress, maintaining a high alert, and was ready to defeat any provocation, Reuters news agency reports.
https://www.bbc.co.uk/news/world-asia-62704449