The Philippines said Wednesday that it has asked China to clarify its reported plans to build an environmental monitoring station on a disputed shoal.
Acting Philippine Foreign Secretary Enrique Manalo told Filipino reporters in the Thai capital Bangkok, where President Rodrigo Duterte is visiting, that his department asked for clarification on the reported planned construction on Scarborough Shoal.
The shoal, off the northwestern Philippines, is at the heart of the territorial disputes between the countries.
"I think the President has been very clear -- we want to have a peaceful, diplomatic settlement of disputes but we will not fail to protect our national interests if necessary," Manalo said.
Asked if a diplomatic protest will be filed, he said Manila will wait for China's reply.
But Manalo said he considered it a good sign that China was interested in concluding a framework for a code of conduct with 10 Southeast Asian nations that aims to peacefully manage disputes in the South China Sea. He said there could be progress on the framework when China hosts a meeting in May.
Any construction would re-ignite concerns over Beijing's increasingly assertive actions to cement its claims in the area, and would be in defiance of last year's ruling by an arbitration tribunal in The Hague that invalidated China's territorial claims in the South China Sea on historical grounds.
Chinese government ships took control of Scarborough in 2012 after a tense standoff with Philippine vessels. China then blocked Filipinos from fishing in the shoal, which has a vast, coral-encircled lagoon that serves as a natural storm shelter for Asian fishermen.
The Philippines brought its disputes with China to international arbitration the following year, but China ignored the complaint and the tribunal's ruling, which found Beijing to have violated the rights of Filipinos to fish at Scarborough.
Since taking office in June, Duterte has put the territorial conflicts with China on the backburner and reached out to Beijing in an effort to revive trade and seek Chinese economic aid. Filipinos have since been allowed to return to Scarborough to fish.