China has rejected US demands to stop its intensifying reclamation works in the South China Sea.
It said it was exercising its sovereignty while helping the rest of the world.
The People's Liberation Army Admiral Sun Jianguo, told a security summit in Singapore that: "the situation in the South China Sea is on the whole peaceful and stable, and there has never been an issue with the freedom of navigation."
"China has carried out construction on some islands and reefs in the South China Sea mainly for the purpose of improving the functions of the relevant islands and reefs, and the working and living conditions of personnel stationed there.
"Apart from meeting the necessary defence needs, it is more geared to better perform China's international responsibilities and obligations regarding maritime search and rescue, disaster prevention and relief, maritime scientific research, meteorological observation, environmental protection, safety of navigation, fishery production, services," he added.
Admiral Sun was speaking one day after US Defense Secretary Ashton Carter demanded an immediate end to China's reclamation works and said Beijing was "out of step" with international norms with its behaviour in disputed waters.