A CHINA Coast Guard (CCG) ship blocked a Philippine research vessel and its escort ship on their way to conduct a hydrographic survey north of Bajo de Masinloc (Scarborough Shoal) in the Philippines' exclusive economic zone (EEZ) over the weekend.

Retired US Air Force Col. Ray Powell, director of SeaLight, a maritime transparency project that monitors and reports activities in the South China Sea, reported on Sunday that CCG 5303 was monitored just 35 nautical miles from the Philippines' coast early Sunday morning when it blocked the path of BRP Hydrographer Ventura and its Philippine Coast Guard (PCG) escort BRP Gabriela Silang to get to their assigned hydrographic research area north of Scarborough Shoal.