Beijing made the move as Vietnam, which is also involved in sovereignty disputes there, adopted a “law of the sea” that placed the Spratlys and Paracel islands under its jurisdiction. Taiwan, Malaysia and Brunei are also involved in various territorial disputes over the island chains and surrounding waters.
In all, Sansha City will be responsible for 13 square kilometers of island area and 2 million square kilometers of water. Since 1959, China had only had a county-level administrative office to exercise sovereignty over the area.
via China Deploying “Military Garrison” to South China Sea? | Flashpoints.
