Image copyright REUTERSImage caption China has built extensively on Mischief Reef and installed military positionsA US warship has sailed close to an artificial island built by China in the South China Sea, the first challenge to Beijing's claim to the waters since President Donald Trump took office.According to unnamed sources cited by US media, the USS Dewey passed within 12 nautical miles of Mischief Reef.China said the US vessel had entered its waters "without permission" and its navy had warned it to leave.The US insists it can conduct operations in any international waters.It says it does not take sides in territorial disputes, but has sent military ships and planes near disputed islands in the past, calling them "freedom of navigation" operations to ensure access to key shipping and air routes.It has also repeatedly criticised what it sees as Beijing's efforts to limit freedom of navigation in the strategic waters.China claims almost all of the South China Sea, including reefs and islands also claimed by other nations. The officials, speaking on condition of anonymity, said the USS Dewey was sailing close to the Mischief Reef in the Spratly Islands, among a string islets, reefs and shoals over which China has territorial disputes with its neighbours.
The USS Dewey sails within 12 nautical miles of the disputed Mischief Reef in the South China Sea.