The US navy’s 7th Fleet said the Arleigh Burke-class guided-missile destroyer USS Ralph Johnson was conducting a “routine” transit through international waters.

“The ship’s transit through the Taiwan Strait demonstrates the US’ commitment to a free and open Indo-Pacific,” 7th Fleet spokesperson Nicholas Lingo said in a statement. “The US military fly, sail, and operate anywhere international law allows.”

China’s defence ministry did not immediately respond to a faxed request for comment. Taiwan’s defence ministry referred questions to the US navy.

Last year, US naval ships transited the Strait roughly monthly. Saturday’s sailing was the first since November.

China claims democratically ruled Taiwan as its own territory and has mounted repeated air force missions into Taiwan’s air defence identification zone (ADIZ) over the past two years, provoking anger in Taipei.

Beijing calls Taiwan the most sensitive and important issue in its relations with Washington.

Like most countries, the US has no formal diplomatic ties with Taiwan but is its most important international backer and arms supplier.