China urged all relevant parties on Wednesday to remain rational and calm and to avoid activities that may further intensify tensions on the Korean Peninsula.

Foreign Ministry spokesman Geng Shuang made the remark after Pyongyang condemned and categorically rejected the latest United Nations Security Council resolution imposing extra sanctions in response to its Sept 3 nuclear test.

The Democratic People's Republic of Korea's foreign ministry said in a statement that the resolution is an infringement on its legitimate right to self-defense and aimed at "completely suffocating its state and people through full-scale economic blockade", Reuters reported.

"The DPRK will redouble efforts to increase its strength to safeguard the country's sovereignty and right to existence and to preserve peace and security of the region by establishing practical equilibrium with the US," Reuters quoted the official KCNA news agency as saying.

The UN Security Council unanimously adopted a new resolution on Tuesday imposing new sanctions on Pyongyang, including limiting its oil imports, banning its textile exports and restricting overseas firms from hiring DPRK citizens.

US President Donald Trump said on Tuesday that the sanctions were "just another very small step" and "nothing compared to what ultimately will have to happen".

Also on Wednesday, the Republic of Korea Air Force said it had successfully conducted its first live-fire exercise for Taurus, a long-range air-to-surface missile for precision bombing, Yonhap News Agency reported.

Ruan Zongze, executive vice-president of the China Institute of International Studies, said the escalating tension on the Korean Peninsula is unsustainable and there must be a way to stop it.

"The priority now is to cool down and put a brake on the current situation. The US, ROK and DPRK should create the necessary conditions for contact and dialogue," he said.

Zhou Jin contributed to this story.

mojingxi@chinadaily.com.cn