Philippines stops research survey after Chinese 'harassment' in disputed sea

China claims nearly all of the disputed waterway, brushing off rival claims from other countries -- including the Philippines -- and an international arbitration tribunal ruling that its assertion has no legal basis.

In recent months, China has deployed navy and coast guard vessels in a bid to bar the Philippines from strategically important reefs and islands in the South China Sea.

Three Chinese coast guard vessels and four smaller boats made "aggressive maneuvers" towards two Philippine Bureau of Fisheries and Aquatic Resources ships and their inflatable boats on Friday near Thitu island, a Philippine Coast Guard statement said.

The Filipino vessels were transporting scientists intending to conduct a "marine scientific survey and sand sampling" at a sandbar off Thitu, the largest Philippine-occupied island in the disputed Spratlys chain, the coast guard said.

Thitu lies about 430 kilometers (267 miles) from the major Philippine island of Palawan and more than 900 kilometers from China's nearest major landmass of Hainan Island.

Chinese forces garrison the Subi Reef near Thitu.

Manila's coast guard said a Chinese navy helicopter "hovered at an unsafe altitude" above the Philippine fisheries agency's inflatable boats on Friday, "creating hazardous conditions due to the propeller wash".

"As a result of this continuous harassment and the disregard for safety exhibited by the Chinese maritime forces", the Philippine Coast Guard said it and the fisheries agency "regrettably suspended their survey operations and were unable to collect sand samples" from unoccupied sandbars off Thitu.

Despite the "dangerous confrontations", no accidents occurred, the coast guard added.

The Chinese foreign affairs ministry and Beijing's embassy in Manila did not immediately respond to requests for comment from AFP.