Beijing has protested after the U.S. Navy reportedly sailed within 12 nautical miles (22 km) of one of China's man-made islands in the disputed South China Sea — the first so-called freedom of navigation patrol under the administration of President Donald Trump.

The operation, which involved the USS Dewey, a guided-missile destroyer, was conducted Wednesday around Mischief Reef in the Spratly chain of the strategic waterway, The Wall Street Journal and Reuters reported, citing anonymous U.S. officials.

Freedom of navigation patrols (FONOPS) represent "a challenge to excessive maritime claims," according to the U.S. Defense Department. The significance of the distance of 12 nautical miles derives from the U.N. Convention on the Law of the Sea (UNCLOS), which generally grants coastal states jurisdiction over seas within 12 nautical miles of the coast.