China has insisted on its "indisputable claim" over Ayungin Shoal in the West Philippine Sea, but the Armed Forces of the Philippines said the basis for its contention is "disputable."

China on Saturday condemned the Philippines' conduct of a rotation and resupply mission to the troops stationed on the BRP Sierra Madre at Ayungin Shoal, a submerged reef in the Spratly Islands located 105 nautical miles west of Palawan.

China Coast Guard spokesperson Gan Yu recently claimed that two supply ships and two coast guard vessels from the Philippines "intruded into the adjacent waters of Ren'ai Reef in China's Nansha Islands without the permission of the Chinese government" on 4 October.

"China has indisputable sovereignty over the Nansha Islands, including the Ren'ai Reef and its adjacent waters, and firmly opposes the illegal delivery of construction materials by the Philippines to the illegally grounded warship," Gan said.

China calls Ayungin Shoal, Ren'ai Reef and the Spratlys, Nansha.

AFP spokesperson Col. Medel Aguilar refuted Gan's statements.

"The use of the word 'indisputable' is disputable. For the reason that number one, the UNCLOS (United Nations Convention on the Law of the Sea) says they don't have sovereignty over the terrain," he said in a weekly news forum in Quezon City.

"That's very far from Nansha, so how can they exercise sovereignty in a low-tide elevation that is not even subject to appropriation or possession?" he said.

China facing global isolation

Aguilar stressed that China has no claim to the territorial waters based on the rulings of UNCLOS.

"There is an arbitral award that says their claim is not valid, including the activities they are conducting there," he added.

He said China only leads itself into "global isolation" over its "irresponsible actions" in the WPS.

"Several countries have expressed openly their support for our position, but not a single country is brave enough to say that they are right," Aguilar emphasized.

"So I think this should be an enlightenment [on China's part], information that they should know about because their actions are leading to their global isolation," he said.

Gan bluntly accused the Philippines of "trespassing" in its claimed territorial waters near Ren'ai Reef when the Philippines conducted a resupply mission to the stationary Sierra Madre.

"The Chinese Coast Guard, following the law, strictly warned the Philippine vessels, tracked and monitored them all the way, and effectively regulated them," the Chinese official said.

No business in WPS

Aguilar, meanwhile, slammed Gan for his remarks and stressed that China has no business intruding on the Philippines' missions in its exclusive economic zone.

"What we do to our BRP Sierra Madre is none of their business because it's our responsibility, and they should not interfere," he said.

"We will find out how the situation will improve further because it cannot be always this way, that there will be harassments, that there will be blocking operations or some kind of blocking, and shadowing and all those harassments," he added.

Despite these incidents in the WPS, Aguilar "confidently" noted that the morale of the soldiers of the AFP's Western Command "remains high."

"They are determined to do, to work harder, to make sure that the interest of the country is protected," he said.