Malacanang raised concern on Thursday on the possibility of China deploying "nuclear element" in the artificial islands in the South China Sea.

Presidential Spokesperson Harry Roque was reacting to the United States' Department of Defense warning that China might bring nuclear weapons in Mabini Reef, McKennan Reef, Burgos Reefs, and Calderon Reefs to power these artificial islands.

"We are concerned about the entry of any and all nuclear weapons into the Philippine territory because our Constitution provides that we are nuclear-free zone," he said in a press briefing.

Roque also cited the Southeast Asian Nuclear-Weapon-Free Zone treaty declaring the whole Southeast Asian areas as a nuclear-free zone.

"We are concerned about the possibility that any foreign power, be it American, Russian, Chinese may bring nuclear warhead into our territory and into ASEAN, which is declared as a nuclear-free zone," he said.

"So the concern is against all possible nuclear-carrying vessels from all countries," he added.

The US report noted that in 2017, China indicated development plans could be underway to power islands and reefs in the typhoon-prone South China Sea with floating nuclear power station and development was reportedly to begin before 2020.

Meanwhile, Roque said President Rodrigo Duterte has not yet changed his friendly stance with China despite his recent warning that further conflict might erupt if Beijing unilaterally gets oil in the West Philippine Sea.

Duterte also recently hit China for shooing away a Philippine Air Force plane flying over the disputed water.

"He has never changed his tune. He has been consistent. It's just that, there's no point openly picking up a fight with China because that's counterproductive," Roque said.

He reiterated that the Philippines would not give up its territory.

"But we will now move on areas that we can agree upon and maintain the status quo on areas that we cannot agree upon," he added. Celerina Monte/DMS