The General said the defensive structures were required in order to display China's claim to sovereignty over the crucial waterway

A Chinese general says China needs to build defensive structures on islands in the South China Sea to display its claim to sovereignty over virtually the entire crucial waterway.

However, the vice president of China's Academy of Military Sciences, Lt. Gen. He Lei, also declined to comment on aircraft deployments on artificial islands Chinese has built in the area, saying those were entirely China's domestic affair.

He met with Chinese and foreign journalists on Thursday on the sidelines of the annual session of China's ceremonial legislature, of which he is a member.

Earlier on Thursday, Foreign Minister Wang Yi blamed "some outside forces" for stirring up trouble in the South China Sea, which is claimed in all or in part by China and five other countries.