For the first time this year, the United States has sent two warships through the strategic Taiwan Strait, according to the Taiwanese government.
The move risks further heightening tensions with China, which considers Taiwan a breakaway province and has not ruled out the use of force to bring the self-ruled island under its control.
It is also likely to be viewed in Taiwan as a sign of support from US President Donald Trump’s administration amid growing friction between Taipei and Beijing.
Taiwan’s defence ministry said in a statement late on Thursday the US ships were moving in a northerly direction and that their voyage was in accordance with regulations.
It added that Taiwan closely monitored the operation to “ensure the security of the seas and regional stability”.
There was no immediate comment from the Chinese government.
China has stepped up pressure on Taiwan since President Tsai Ing-wen, from the pro-independence ruling party, took office in 2016. It has regularly sent military aircraft and ships to circle the island on drills in the past few years.
Beijing sent several bombers and aircraft through the Bashi Channel, which separates Taiwan from the Philippines, earlier on Thursday, Taiwan’s defence ministry said in a separate statement.
A similar Chinese operation was conducted on Tuesday, the ministry said, and both were monitored closely.
In a speech in early January, Chinese President Xi Jinping said China reserves the right to use force to bring Taiwan under its control. In response, Tsai vowed to defend the island’s democracy and called for international support to protect Taiwan’s way of life.
Taiwan’s military has hosted multiple drills since Xi’s speech, emphasising what it says is a readiness to counter any invasion.
On Thursday, the navy showed off its new, long-range surveillance drone, the “Rui Yuan” (Sharp Hawk), which officials said can fly for 12 hours and was now helping to monitor movements in the disputed strait between Taiwan and China.
“The drones are now an irreplaceable part of our reconnaissance strategy,” Taiwan defence ministry spokesman Chen Chung-chi told AFP news agency. “They are our primary option for activities in the strait.”
Trump recently signed into law the Asia Reassurance Initiative Act reaffirming the US commitment to Taiwan, including arms sales.
Washington has no formal ties with Taiwan but is bound by law to help it defend itself and is its main source of weapons.