Tuesday’s “routine” operation involving the Arleigh Burke-class guided-missile destroyer USS Curtis Wilbur was announced by the the U.S. Navy’s Seventh Fleet, headquartered in Yokosuka, Japan.

The transit was “in accordance with international law” and “demonstrates the U.S. commitment to a free and open Indo-Pacific,” the statement said. “The United States military will continue to fly, sail, and operate anywhere international law allows,” it added.

Zhang Chunhui, a spokesperson for the People’s Liberation Army’s Eastern Theater Command, described the Navy’s operation as a “publicity stunt,” which he said “sends the wrong signal to Taiwan independence forces.”

The U.S. is “disrupting the region” and “endangering peace and stability across the Taiwan Strait,” he added while noting Beijing’s “strong opposition” to the matter.

Taiwan has no formal diplomatic ties with Washington but relies on the U.S. to supply crucial defensive arms in order to deter China’s constant threat of attack and occupation.

Satellite images taken on May 18 appeared to show the USS Curtis Wilbur approaching the Taiwan Strait “median line.” China does not recognize the maritime demarcation and last year sent several warplanes across it, but the Taiwanese government says the line has acted as a buffer to prevent military accidents for decades.

Zhang, who said the Chinese military monitored the U.S. warship throughout its journey, lodged a similar protest in February when the USS Curtis Wilbur last appeared in the Taiwan Strait, which is around 80 miles in width at its narrowest point.

Taiwan’s Defense Ministry on Wednesday also noted the destroyer’s presence the day before, describing the situation around the island as normal during the U.S. Navy vessel’s southbound passage.

The U.S. military has averaged one Taiwan Strait transit every month since President Joe Biden took office in January. On February 4, the USS John S. McCain became the first American warship to pass through the waters in 2021, before returning again in early April.

It remains to be seen whether the regular destroyer operations between Taiwan and China will surpass the current annual record of 13 set during former President Donald Trump’s administration in 2020.

In April, the Chinese military said it had lodged a diplomatic complaint over the conduct of the Arleigh Burke-class destroyer USS Mustin, which it accused of “persistent close-range reconnaissance.”

Chinese Defense Ministry spokesperson Wu Qian said the warship had disrupted the training exercises of China’s aircraft carrier Liaoning in April—an accusation the U.S. Navy denied.

U.S. presence in the seas and skies around China has increased in recent years in response to Beijing’s own growing military might and its territorial assertions in the region.

Research out of the Chinese capital has noted an uptick in U.S. freedom of navigation operations and overflights, especially in the contested South China Sea.