The USS Lassen was accompanied by Navy surveillance planes as it approached the Subi Reef in the Spratly Islands. (Reuters File Photo)
A US naval destroyer sailed early Tuesday within 12 nautical miles of an artificial island built by China in the South China Sea, a US defense official said, in a direct challenge to China's territorial claims.
The USS Lassen, a guided-missile destroyer, was accompanied by Navy surveillance planes as it approached the Subi Reef in the Spratly Islands, the official said.
The mission "was completed without incident," said the official, who spoke on the condition of anonymity.
The action is certain to anger China, which said last month it would "never allow any country" to violate its territorial waters and airspace around the islands.
Chinese Foreign Minister Wang Yi had said earlier that Beijing was trying to verify whether the US vessel had entered the 12-mile zone.
"If true, we advise the US to think again, not to act blindly or make trouble out of nothing," the Foreign Ministry quoted him as saying.
The US mission was also intended to test a pledge made by President Xi Jinping during his visit to Washington last month that Beijing would not militarize the islands, US officials have said.
Subi Reef, which lies close to the Philippines in the South China Sea, used to be submerged at high tide before China began a massive dredging project to turn it into an island. It is now big enough to potentially host an airstrip.
Satellite images also show what looks like a surveillance tower and multiple satellite antennas, according to the Asia Maritime Transparency Initiative, part of the Center for Strategic and International Studies.
Under the international law of the sea, turning such features into artificial islands does not imply any rights to territorial waters around them, something the US mission is designed to underline.
The Chinese Embassy in Washington said that the concept of freedom of navigation should not be used as an excuse for muscle-flexing and that the United States should "refrain from saying or doing anything provocative and act responsibly in maintaining peace and regional stability," Chinese state media reported.
The USS Lassen, an Arleigh Burke-class guided-missile destroyer, operates out of its home port in Yokosuka, Japan - headquarters for the US 7th Fleet.
The Lassen has been deployed to the South China Sea since late May and has had several routine interactions at sea with Chinese naval vessels, according to US Navy officials.
© 2015 The Washington Post