The Philippine coast guard says Chinese coast guard ships and a Chinese navy helicopter harassed a group of Philippine fisheries vessels conducting a scientific survey in a hotly disputed area of the South China Sea, forcing them to cancel the operation. The harassment took place Friday near Sandy Cay, three small uninhabited sandbars planked by an artificial island base of Chinese forces and a Philippines-occupied island in the Spratlys archipelago, the coast guard said. The coast guard ships approached two larger vessels, which maneuvered to avoid a collision, and a Chinese navy helicopter flew low over two smaller boats, forcing the survey to be called off. There was no immediate comment from China.