But given the importance of nuclear non-proliferation and preventing terrorists from laying their hands on nuclear weapons or materials, China attended the summit and emphasized multilateral rather than bilateral cooperation with the US to address the issues.

In Washington, Xi firmly supported international partnership to foster a global nuclear security community. In collaboration with the US, China recently opened its State Center of Excellence on Nuclear Security to help improve the technical expertise of nuclear scientists and other experts both at home and abroad. The center is essentially a joint venture of China and the US for the nuclear security of China and the Asia-Pacific.

We have to understand that the Nuclear Security Summit is more of a legal and technical arrangement aimed at thwarting nuclear theft and sabotage. Under the summit's framework, Beijing and Washington are engaged in converting research reactors fueled by highly enriched uranium to those that can run on low enriched uranium. The first such conversion was completed at a plant near Beijing recently. To echo the call of these summits, China will also work with the US and the International Atomic Energy Agency to convert a similar reactor it exported to Ghana.

China not only supports international efforts to ensure nuclear security, but also aspires to play a leading role in global security governance. At the summit, China said it will launch its action plan to make radioactive sources totally secure. China will also strengthen supervision of nuclear energy security arrangements, and help other countries do the same with their arrangements.

Being a major power with a strong sense of principle and responsibility, China is fast emerging as a regional and global security guardian. And it will implement the policy recommendations of the Nuclear Security Summits for its own security as well as to help build a robust regional nuclear security community.

The author is a professor at and associate dean of the Institute of International Studies, Fudan University.