Still image from United States Navy video purportedly shows Chinese dredging vessels in the waters around Mischief Reef in the disputed Spratly Islands

Chinese dredging vessels are purportedly seen in the waters around Mischief Reef in the disputed Spratly Islands in the South China Sea in this still image from video taken by a P-8A Poseidon surveillance aircraft provided by the United States Navy May 21, 2015. REUTERS/U.S. Navy/Handout via Reuters