Photo: (DigitalGlobe/Getty Images) DigitalGlobe satellite imagery shows the Subi Reef in the South China Sea, a part of the Spratly Islands group, May 28, 2018.

Photo: (DigitalGlobe/Getty Images) DigitalGlobe satellite imagery shows the Subi Reef in the South China Sea, a part of the Spratly Islands group, May 28, 2018.