National Security Adviser Hermogenes Esperon Jr. admitted on Friday it was not surprising if China really installed anti-ship cruise missiles and surface-to-air missile systems on three of its outposts in the South China Sea.

In an interview at the sidelines of the 51st Asian Development Bank Meeting in Mandaluyong City, Esperon, said that there was no way for the Philippines to confirm the latest report.

"We have been getting reports of that. We have been told about it but we have no way of verifying," he said.

He said the Philippine government was just relying from its friends who have been giving the information.

"But is it surprising to know that some cruise missiles - is it surprising to find out that there will be deployment of such after we allowed them to build airstrips in the three islands? Is it surprising to learn that those things could be deployed there? I'm not," Esperon said.

He added he would not be surprised if China would continue to install more military equipment in the artificial islands that it built in the disputed South China Sea.

"I'll just assume that the report is correct because it is very probable. Why? Because the airstrips are there. There are construction that have been finished there and we know that it could further go on...so other armaments could come in," Esperon said.

Reports said China installed missile systems in the Philippine-claimed Panganiban, Zamora and Kagitingan reefs in the South China Sea.

Asked what the Philippines would do if it was true that China installed anti-ship cruise missiles and surface-to-air missile systems in its controlled artificial islands, Esperon said the "least" the Duterte administration could do is to file a diplomatic protest.

He reiterated that Manila could not go to war with Beijing. "We can employ our economic powers, but we would rather do that in getting more trade with China or other countries," he said.

China has promised multi-billion dollars of assistance to the Philippines in terms of grants and loans as President Rodrigo Duterte has decided to take a softer stance insofar as the territorial dispute with China is concerned contrary to his predecessor.

Former President Benigno Aquino III's administration brought a case before the United Nations Arbitral Tribunal seeking to invalidate China's historic claim through nine-dash line in South China Sea. The arbitration court ruled in favor of the Philippines. Up to now, China refused to honor the award.

Esperon admitted that he is more concerned about the internal threats in the country.

"My concern really is how to make this nation internally strong," he said, citing the need to defeat the communist New People's Army and the Muslim rebels and terrorists. Celerina Monte/DMS