Experts however, warn that Manila’s strategy of having several warships patrolling at once could strain resources and leave the navy vulnerable to targeted attacks.

The Philippines won a landmark case at the Permanent Court of Arbitration in 2016 that found China's sweeping claim of sovereignty in the South China Sea had no basis under international law. It now wants to hold Beijing accountable for what it says is its harvesting of giant clams and substantial environmental damage to coral reefs in the Philippines' exclusive economic zone.

US Secretary of State Marco Rubio reaffirmed Washington's commitment to Manila and condemned Beijing for its "dangerous and destabilising" actions in the Sea, in his first phone call with Philippine Foreign Secretary Enrique Manalo.