The head of Beijing's Office for Safeguarding National Security in Hong Kong on Monday said national security is the SAR's top priority and ongoing effort is needed to maintain social stability.

Dong Jingwei told an opening ceremony for National Security Education Day that Hong Kong is highly open and susceptible to external threats, and its destiny is closely tied to that of the country.

"During critical times of reform, it's more important than ever to unite. During key phases of development, our national security becomes even more important. Maintaining social stability and national security in Hong Kong isn't a one and done process," he said.

Meanwhile, Li Yongsheng, deputy commissioner of the Foreign Ministry's office in Hong Kong, said he believes the city will thrive with the strong support of the nation.

"We firmly believe that with the strong backing of the great motherland, Hong Kong will be able to achieve higher quality development and higher level of openness under a higher level of security and speed up the beautiful process from stability to prosperity," he said.

Wang Zhaobing, deputy political commissar of the People's Liberation Army in the SAR, said the Hong Kong garrison will strengthen military training to safeguard national sovereignty and the long-term prosperity of the territory.