The Philippines has turned down offers from the United States to assist operations in the South China Sea, after a flare-up with China over missions to resupply Filipino troops on a contested shoal, its military chief said.

Tensions in the disputed waterway have boiled over into violence in the past year, with a Filipino sailor losing a finger in the latest June 17 clash that Manila described as "intentional-high speed ramming” by the Chinese coast guard.

The U.S., a treaty ally, has offered support but Manila prefers to handle operations on its own, Armed Forces Chief Gen. Romeo Brawner said late Thursday.