Washington's top defense official urged claimant states in the South China Sea, including the Philippines, to assert sovereign rights in the disputed waterway.

The Philippine Coast Guard sent off crew members of two multi-role response vessels that will patrol the country's territorial waters.

The ship, which has yet to be named, is Beijing's second carrier and will add massive firepower to its navy once it is officially put into service as it faces tensions with self-ruled Taiwan and regional neighbors around the disputed South China Sea.