The presence of Chinese research vessels in Benham Rise was "a clear intrusion" into the Philippine maritime territory, President Marcos said.
"Once again, this is a clear intrusion into our Philippine maritime territory and it is, as usual, of great concern," Marcos said in an interview in Melbourne, Australia on Wednesday, March 6.
He was referring to the reported sightings of Chinese research vessels in Benham Rise.
The President also raised suspicion that the vessels are not only for research purposes, stressing that if they were, there could have been an official agreement that the Chinese vessels would ply the country's waters.
"I see this as absolutely unnecessary because if it is truly a research vessel then we could have come to a very simple agreement that the research vessel will ply the waters and do the research that they need to do," he said.
"However, there is a suspicion that they are not only research vessels so, again, this is a bit of an escalation of the tension that is present in the West Philippines Sea," he added.
According to the Philippine Navy, the vessels were spotted 800 nautical miles east of Casiguran, Aurora as of Sunday, March 3.