Manila, Aug. 1 -- The Philippine Coast Guard (PCG) is closely monitoring three Chinese research vessels operating without authorisation inside the country's exclusive economic zone (EEZ), raising alarms over potential illegal marine scientific research (MSR) activities in contested waters of the South China Sea, Singapore-based Maritime Fairtrade reported.

Using satellite data from Canada's Dark Vessel Detection Program, the PCG identified the vessels Bei Diao 996, Zhuhaiyun, and Xiang Yang Hong 10 within the West Philippine Sea, part of the South China Sea claimed by the Philippines under international law.

"These vessels are suspected of engaging in illegal marine scientific research, prompting the PCG's commandant, Admiral Ronnie Gil...