The Philippines has asked an international tribunal to declare as invalid China's claims to virtually all of the South China Sea, saying Beijing's actions have trampled other nations' rights and irreversibly damaged coral reefs.

Foreign Secretary Albert del Rosario told the tribunal in The Hague on Tuesday that China's strategy was to gradually take control of the sprawling waters without sparking a crisis. Philippine officials provided his statement to journalists in Manila on Wednesday.

The tribunal opened hearings to address China's contention that the arbitration body does not have authority to assume jurisdiction over the Philippine complaints. China claims the seas on historical grounds and wants one-on-one negotiations instead of arbitration.

Countries territorially at odds with China — Japan, Vietnam, Malaysia — were among those sending observers to the hearings.