A US warship carried out a “maneuvering drill” when it sailed within 12 nautical miles of an artificial island built up by China in the South China Sea, to show it was not entitled to a territorial sea around it, US officials said on Thursday. The operation, which took place near Mischief Reef on Thursday, Pacific time, among a string of islets, reefs and shoals over which China has disputes with its neighbors, was the boldest US challenge yet to Chinese island-building in the strategic waterway, according to Reuters. It drew an angry response from Beijing. Previous US “freedom of navigation operations” in the Spratly archipelago have involved “innocent passage,” in which a warship effectively recognizes a 12-nautical-mile territorial sea by crossing it speedily, without stopping. On Thursday, the destroyer USS Dewey conducted a “man overboard” exercise, specifically to show that its passage of the warship within 12 nautical miles was not innocent passage, US officials said, speaking anonymously.