Beijing: China is in a bind over what to do about North Korea's stepped-up nuclear and missile tests, even though it is annoyed with its ally and has started talks with other UN Security Council members on a new sanctions resolution against Pyongyang.

China shares a long land border with North Korea and is seen as the only country with real power to bring about change in the isolated and belligerent nation.

North Korean leader Kim Jong-un laughs as he watches a winter river-crossing attack drill. Credit:KCNA

However, Beijing fears strengthening sanctions could lead to collapse in North Korea, and it also believes the United States and its ally South Korea share responsibility for growing tensions in the region.

China is in a difficult spot, a source close to the Chinese leadership said when asked if Beijing's attitude to North Korea had changed after its fifth nuclear test earlier this month .