China said on Thursday that it faces heavy demands in safeguarding national security as it is confronted by "more diverse and complex" security challenges.

"China has vast territories and territorial seas. It is in a critical phase of the building of a moderately prosperous society in an all-round way. Therefore, it faces heavy demands in safeguarding national security," says the white paper, issued by the Information Office of the State Council on Thursday.

The white paper says the "Taiwan independence" separatist force and its activities are still the biggest obstacle and threat to the peaceful development of cross-Strait relations. Further progress in cross-Strait relations is still confronted by some complicating factors.

Separatist forces working for "East Turkistan independence" and "Tibet independence" have inflicted serious damage on national security and social stability, says the white paper.

"Pressure builds up in preserving China's territorial integrity and maritime rights and interests. Non-traditional security concerns, such as existing terrorism threats, energy resources, finance, information and natural disasters, are on the rise," it says.

Suspicion about China, interference and countering moves against China from the outside are on the increase. The United States, in defiance of the three Sino-U.S. joint communiques, continues to sell weapons to Taiwan, severely impeding Sino-U.S. relations and impairing the peaceful development of cross-Strait relations, according to the white paper.

"In the face of the complex security environment, China will hold high the banner of peace, development and cooperation, adhere to the concepts of overall security, cooperative security and common security, advocate its new security concept based on mutual trust, mutual benefit, equality and cooperation," says the white paper.