China has closed off an area of the South China Sea this week for military training.

The China Maritime Safety Administration says drills are being held all day Sunday and half a day Tuesday in an area near China's holdings in the Paracel island group.

China claims virtually the entire South China Sea as its own territory and strongly objects to naval activity in the area by other nations.

Another five governments exercise overlapping claims, particularly in the Spratly islands to the east.

The waterway rich in fishing grounds through which passes an estimated $5 trillion in global commerce annually has become a global security hotspot, largely due to growing Chinese assertiveness in pressing its claims.

China has built man-made islands to expand its footprint.