Philippine President Rodrigo Duterte said Thursday he has ordered troops to deploy on unoccupied South China Sea islands and reefs claimed by Manila, in a move that could provoke rival claimants including Beijing.

"It looks like everybody is making a grab for the islands there, so we better live on those that are still vacant," he told reporters during a visit to a military camp on the western island of Palawan, near the disputed Spratly group.