Authorities in the Philippines have lodged a protest with Beijing for unilaterally claiming an area of the South China Sea that lies within Manila's exclusive economic zone.

Officials in Beijing said on Sunday they've revised China's territorial baseline. They included Scarborough Shoal, which is effectively controlled by Beijing despite being in the Philippines' EEZ.

Officials at the Philippine National Maritime Council issued a statement on Tuesday. They say territorial waters should be based on conditions set by the United Nations Convention on the Law of the Sea. They also say China's announcement lacks legal basis.

Chinese Foreign Ministry spokesperson Lin Jian said on Tuesday that all escalations in maritime disputes between China and the Philippines were triggered by infringements and provocations on Manila's part.

Chinese media say the Chinese Coast Guard is stepping up patrols in the area to deal with any provocations by the Philippines.