MANILA—The Philippines on Friday warned China against letting its military exercises in the South China Sea spill over into Philippine territory.

In a strongly worded video statement, Foreign Affairs Secretary Teodoro Locsin Jr. said it would be met with “with the severest response” should the Chinese People’s Liberation Army’s exercises on the Paracel Islands cross over Philippine territory.

Vietnam has competing claims of the islands.

“Should the exercises spill over to Philippine territory, then China is forewarned that it will be met with the severest response, diplomatic and whatever else is appropriate,” Locsin said.

Locsin also reiterated that China’s creation of Xansha city “is null and void ab initio for being devoid of basis in international law.”

“This is the problem with playing fast and loose with historical narratives and historical names. They open themselves to error unless the real purpose is to excuse and challenge mistakes that may over time harden into rights,” Locsin added.

In April, the Philippines filed diplomatic protests against China over the pointing of a radar gun at a Philippine Navy ship in Philippine waters and declaring parts of the Philippine territory as part of Hainan province, “violating international law and Philippine sovereignty.”

Manila also objected to China’s naming of some features in the Kalayaan island group, saying the Philippines does not recognize them.

The DFA invoked the 2016 arbitral win of the Philippines under the United Nations Convention on the Law of the Sea (UNCLOS), saying it “has comprehensively addressed China’s excessive claims and illegal actions in the South China Sea.”