MANILA • The Philippines will lodge a protest over the unannounced presence of two Chinese research vessels in its exclusive economic zone (EEZ), one of at least three diplomatic challenges in recent weeks amid a souring of relations.
The protest comes ahead of President Rodrigo Duterte's planned visit to Beijing this month, during which he has promised to raise Manila's South China Sea international arbitration victory over Beijing with President Xi Jinping, having avoided confronting the thorny issue for three years.
Historically frosty bilateral relations had warmed under Mr Duterte, but he is looking increasingly awkward in defending his controversial approach to China amid constant activity by its coast guard, navy and paramilitary fishing vessels in Philippine-controlled areas of the South China Sea.
"Firing off diplomatic protest," Foreign Affairs Secretary Teodoro Locsin said in a tweet yesterday.
The Philippines on July 31 protested against the presence of more than 100 Chinese fishing vessels off Thitu island, a tiny island it holds near China's militarised artificial island at Subi Reef.
It has also protested against the unannounced passage of Chinese warships within the Philippines' 19km territorial sea, which Defence Secretary Delfin Lorenzana yesterday said had happened on several occasions since February.
The latest protest centres on the lingering presence of two Chinese scientific research boats off the Philippines' Pacific coast, within the 322km EEZ.
Mr Lorenzana told news channel ANC that like other countries conducting research, or moving warships near its coastline, China should have informed the Philippines about it.
"We can always protest to the Chinese government. It's telling them we know what you are doing and please tell us what you are doing there," he said.
China's embassy in Manila did not immediately respond to a request for comment.
Mr Duterte on Thursday called for a quicker creation of a code of conduct between South-east Asian countries and China for the South China Sea, a conduit for in excess of US$3.4 trillion (S$4.7 trillion) of goods each year.
The Philippines, China, Vietnam, Taiwan, Brunei and Malaysia have overlapping claims of sovereignty within the South China Sea.
China says it has historic jurisdiction to almost the entire sea, although the 2016 arbitral ruling declared that invalid under international law.