The Philippines said on Saturday it has suspended a scientific survey in the South China Sea after two of its fisheries vessels faced "harassment" and aggressive behaviour from China's coast guard and navy.

US Secretary of State Marco Rubio reaffirmed Washington's commitment to Manila and condemned Beijing for its "dangerous and destabilising" actions in the Sea, in his first phone call with Philippine Foreign Secretary Enrique Manalo.

The Philippines will soon decide on an international platform to sue China for alleged damage to the marine environment, its justice minister said, as it pursues a second high-profile legal challenge against Beijing over the South China Sea.

Beijing and Manila have agreed to continue talks on settling their territorial differences despite Philippine protests about the presence of a Chinese "monster ship" near the contested Scarborough Shoal.

Videos released showed a Chinese coast guard ship sailing close to a Philippine vessel as well as a Chinese military helicopter hovering near a ship flying a Philippine flag.

China's coast guard said the Philippines on Friday sent a civilian vessel to deliver provisions to its warship "illegally grounded" at Second Thomas Shoal, a disputed atoll in the South China Sea.

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,