The greatest challenge, however, would pose China's "compulsive and increasingly aggressive efforts to reshape the Indo-Pacific region and the international system to suit its interests and authoritarian preferences," the document said.

In particular, reference is made to the rhetoric of the Chinese leadership towards Taiwan. Beijing regards the island as a breakaway province that is to be reunited with the mainland - if necessary using military force.

In addition to the new National Defense Strategy, the US Department of Defense released a new nuclear weapons strategy. It emphasizes that US nuclear weapons serve as a deterrent against "all forms of strategic attack". "This includes nuclear weapon deployments of all sizes, and it includes strategic attacks with serious consequences by non-nuclear means."

The Pentagon sends a clear warning to North Korea in the document. "Any nuclear attack by North Korea against the United States or its allies and partners is unacceptable and will lead to the end of the regime. There is no scenario in which the Kim regime could use nuclear weapons and survive," said North Korean ruler Kim Jong U.N.

North Korea recently carried out a series of missile tests, drawing sharp international criticism. There are also fears that Pyongyang could soon carry out a nuclear test.

fs/dja