The Philippines is concerned about China's possible deployment of nuclear weapons in its outposts in the heavily disputed South China Sea.
"We are concerned about the entry of any and all nuclear weapons into the Philippine territory because our Constitution provides that we are a nuclear-free zone," Presidential Spokesperson Harry Roque said on Thursday.
Roque also cited that there is an Asean treaty declaring the whole Asean as a nuclear-free zone.
"We are concerned about the possibility that any foreign power be it American, Russian, Chinese may bring nuclear warheads into our territory and into Asean, which is declared as a nuclear-free zone," he said.
A United States' Department of Defense had earlier warned that China may deploy nuclear weapons in the South China Sea, where the Asian superpower has a sweeping claim.
While Roque said that the warning was a mere "US observation," he said the Philippines was against any deployment of nuclear weapons in areas declared as nuclear-free zones.
"The important point to underscore is we have a nuclear-free policy and that should be applied to all countries, including the Americans, because the Americans have been using nuclear-powered [weapons] and have been stationing warships with nuclear capability as well," he said.
"So the concern is against all possible nuclear-carrying vessels from all countries," he said.
Asked if the government would verify the US warning, he said, "That's a US observation. We are not in the position to verify that. And as we correctly said it is even in the nature of speculation. It is a possibility according to American sources so we leave it at that."
"You know, if we could, we will try verifying it, try approaching any of these suspected nuclear warheads," he added with hesitation, saying "I don't think they can be boarded."