A US warship sailed through the Taiwan Strait in what the American military described as a “routine” passage Wednesday, but enraging China, which claims sovereignty over the island and surrounding seas.

Ties between Beijing and Washington have deteriorated in recent months, over issues including trade and Hong Kong, with the self-ruled island of Taiwan a long-running source of tension.

The guided-missile destroyer USS Barry passed through the Strait on October 14, according to a statement by the US Pacific Fleet.

“The ship’s transit through the Taiwan Strait demonstrates the US commitment to a free and open Indo-Pacific,” the statement said.

“The US Navy will continue to fly, sail and operate anywhere international law allows,” it added.

Any US Navy operations in the Taiwan Strait, which separates China from the island, provoke a strong response from Beijing, which considers Taiwan to be an inviolable part of its territory.

In an angry riposte, the Chinese People’s Liberation Army said it tracked the USS Barry by sea and air “throughout the entire process.”

“We warn the US to stop its words and deeds that provoke trouble and disturb the situation in the Taiwan Strait,” Eastern Theatre Command spokesman Colonel Zhang Chunhui said.

The island has been governed separately since the end of a civil war in China in 1949.

Taiwan has its own flag, currency and military, but it is not recognized as an independent nation by the UN.

Washington ended its diplomatic relations with Taipei in 1979 in order to improve ties with China, but the US remains the island’s most powerful ally and its main arms supplier.

The Chinese have threatened to use force if Taipei proclaims independence or if there is foreign intervention.

Beijing views the passage of foreign vessels through the Strait as a violation of its sovereignty.

Washington and many other countries, on the other hand, see the waterway as part of international waters and therefore open to all.