North Korea has condemned the United States and South Korea for signing a new set of guidelines for nuclear deterrence and nuclear operations on the Korean Peninsula.

US President Joe Biden and South Korean President Yoon Suk-yeol endorsed the guidelines in Washington on Thursday. The document will serve as a basis from which the two countries' nuclear deterrence against North Korea can be strengthened.

A spokesperson for North Korea's defense ministry issued a statement through the country's state-run news agency on Saturday.

In it, the spokesperson accuses the United States and South Korea of stepping up preparations for a nuclear war with the North.

The statement says the threat posed by North Korea's enemies urgently requires Pyongyang to further improve its nuclear deterrent readiness.

It goes on to say that the US and South Korea "will have to pay an unimaginably harsh price," if they commit more provocative acts.

North Korea has also denounced a declaration adopted at the latest NATO summit, accusing Pyongyang of providing military support to Russia.

The North says that it will conduct another test launch of its new tactical ballistic missile, the Hwasong-11, by the end of the month.