U.S. warship sails within 12 miles of China-claimed reef

A U.S. Navy warship sailed within 12 nautical miles of an artificial island built up by China, U.S. officials said on Wednesday, the first such challenge to Beijing under U.S. President Donald Trump.The officials, speaking on condition of anonymity, said the USS Dewey was traveling close to the Mischief Reef in the Spratly Islands, among a string islets, reefs and shoals over which China has territorial disputes with its neighbors.The so-called "freedom of navigation operation" comes at a time w