The Philippines said yesterday it would protest to China about what it called Beijing's increasing patrols in a disputed area of the South China Sea believed to hold rich oil and gas resources.
Foreign relations department spokesman Charles Jose announced the protest a day after the airing of a television interview in which President Benigno Aquino raised the alarm over the Chinese vessels at Reed Bank.
"The frequent passage of Chinese vessels in Recto Bank is not an innocent exercise of freedom of navigation but is actually done as part of a pattern of illegitimate sovereign patrol in the Philippines' exclusive economic zone, pursuant to China's unilateral effort to change the status quo in the South China Sea," Jose said, referring to Reed Bank by its Filipino name.
He said the latest disputed area was about 160km from the western Philippine island of Palawan, placing it well within the country's internationally recognised exclusive economic control zone.
In contrast, Jose said the bank was 595 nautical miles to the south of Hainan island, which was the nearest Chinese territory.
A day earlier, Aquino expressed concern at the presence of Chinese government ships in the disputed waters, questioning how far China intended to push its claims.
In an interview with ABC-5 television network, transcripts of which were released by the presidential palace, Aquino said: "They want to claim what is ours. How far will we let this go? Are we going to be content to just tell them, 'OK, you can go this far'.
"What are they doing there? What studies are they doing? Hopefully this will not add to the tensions between the two of us."
Defence spokesman Peter Paul Galvez said yesterday the ships were "hydrological research vessels" capable of mapping the ocean floor, adding they were first sighted in June but could remain at sea for over a month.
Aquino joked that China eventually could claim all of the Philippines, citing the presence of Chinese migrants in Manila as early as the 16th century when the archipelago was a Spanish colony.