The injuring of Filipino crew and damage to Philippine vessels in the South China Sea is "irresponsible behaviour and disregards international law", U.S. Defense Secretary Lloyd Austin told a joint press conference on Thursday (May 2).

Philippines Defense Secretary Gilberto Teodoro told the press conference the job was to ensure that through building capacity and deterrence there were no situations where a Mutual Defense Treaty would be triggered.

China claims sovereignty over much of the South China Sea, a conduit for more than $3 trillion of annual ship-borne commerce, including parts claimed by the Philippines, Vietnam, Indonesia, Malaysia and Brunei.

The Philippines summoned Thursday a Chinese diplomat on Thursday to protest Beijing's use of water cannon against Filipino vessels at a disputed shoal in the West Philippine Sea, describing it as harassment and "dangerous maneuvers.”