Regarding warships, customary rules on innocent passage and freedom of navigation codified in the UNCLOS are far from being settled among State Parties. FONOPs impose the US understanding of rules on passage and navigation in each and every sea area, forcefully implementing deregulation in order for the US to create a navyfriendly environment for its worldwide mission. By implementing another agenda of carrying out the new US policy of “Pivot to Asia,” the FONOPs in the South China Sea challenge the very heart of China’s sovereignty, and may bring about adverse effect to the process of peaceful settlement of territorial issues and maritime disputes in the South China Sea region. China believes the US FONOPs in the South China Sea are offensive to its sovereignty. Moreover, their adverse effect to the process of peaceful settlement of territorial issues and maritime disputes in the South China Sea region cannot be ignored.

1. Introduction
 2. USS Curtis Wilbur Incident: the long-lasting controversyon ‘innocent passage’ of war-ships
 3. The USS Lassen Incident: unwanted ‘innocent passage’within 12 nm of Subi Reef
 4. Exercise of Freedom of Navigation by FONOPs aroundthe Chinese ‘Non-offshore’ LTEs in the South ChinaSea
 5. Conclusion

• Xinjun Zhang(Associate Professor of International Law at Tsinghua University)