China's claim in sea legal and justified

The US must also abide by the Notification of Major Military Activities Confidence-Building Measures Mechanism and the Rules of Behavior for Safety of Air and Maritime Encounters, both of which were agreed by the Chinese and US militaries in late 2014, so as to regulate the actions in the sea and the air, maintain the safety and order of military activities in the exclusive economic zone, and ensure the freedom of navigation and safety of vessels.

China raised a good "dual track" proposal last August that the direct dispute parties should seek peaceful settlement of their disputes through friendly negotiations with each other, and peace and stability in the South China Sea should be maintained by China and ASEAN members together.

The proposal, if well implemented, can decrease troubles and confrontations. The proposal also urges relevant parties to abide by the principles and requirements of the Declaration on the Code of Conduct on the South China Sea and promote further negotiations on a code of conduct.

The relevant parties need to strengthen their cooperation in some less sensitive maritime fields to build up mutual trust.

The US should act responsibly and seek to play a constructive rather divisive role in the region. China's proposals and actions should be correctly judged and supported by other responsible countries.

The author is a researcher at and director of Ocean Strategy Studies Center, Shanghai Academy of Social Sciences.