MANILA — A US warship sailed close to a Chinese man-made island in the disputed South China Sea in an operation that challenged China’s vast territorial claims in busy international waters, a US Navy official said Thursday.
The official told The Associated Press that Chinese vessels were in the vicinity when the USS John S. McCain sailed in a ‘‘routine’’ freedom of navigation operation near Mischief Reef Thursday. It was not immediately clear if the Chinese demanded the US destroyer leave as they have done in the past.
The official spoke on condition of anonymity because the official was not authorized to speak to the press about the matter.
China, which claims the South China Sea virtually in entirety, has protested such repeated US military operations, which President Trump’s administration has continued partly to reassure allies locked in territorial rifts with Beijing.
Tensions escalated a few years ago when China began to build seven reefs, including Mischief, into islands, including three with runways, which the United States and China’s neighbors fear could be used to project Beijing’s military might and potentially obstruct freedom of navigation.
China has reportedly installed a missile defense system on the new islands.
The United States is not involved in the long-seething disputes in the busy and potentially oil- and gas-rich waters involving China, Brunei, Malaysia, the Philippines, Taiwan, and Vietnam. Washington, however, has declared it in its interest to ensure that the conflicts are resolved peacefully and that freedom of navigation and overflight remain unhampered.
An estimated $5 trillion in annual trade passes through the waterway.
In the latest sail-by, US military officials notified Philippine counterparts of the maneuver, a Philippine official told the AP, adding Filipino forces were not involved.
Philippine marines stationed in a marooned ship on a disputed shoal may have monitored the US Navy operation because they are based near Mischief Reef, which is also claimed by the Philippines, the official said.
US Pacific Fleet spokeswoman Lieutenant Commander Nicole Schwegman said all Navy operations ‘‘are conducted in accordance with international law and demonstrate that the United States will fly, sail, and operate wherever international law allows.’’
‘‘That is true in the South China Sea as in other places around the globe,’’ she said.
The disputes and North Korea’s recent intercontinental ballistic missile tests were high on the agenda of an annual gathering of Asia-Pacific foreign ministers last weekend in Manila.
Although China opposes inclusion of the sea disputes in international conferences, partly to prevent the US and other Western governments from intervening, Secretary of State Rex Tillerson, Australian Foreign Minister Julie Bishop, and Japan’s new top diplomat, Taro Kono, expressed concern over aggressive actions in the waters.
In the latest operation, US military officials were said to notify their Philippine counterparts of the maneuver.
They sought compliance with an arbitration ruling last year that invalidated China’s claims in the South China Sea. China has ignored and dismissed the ruling as a sham.
Washington’s critical actions came as it courts the help of China, North Korea’s ally, in taming Pyongyang’s nuclear weapons ambitions and ending its missile tests.