North Korea threatens four EU states over sanctions monitoring group

Choe Son-hui also warned that the countries that are part of it will have to "pay a high price."

"I condemn and vehemently reject it as a challenge to international justice and the most blatant violation of North Korea's sovereignty," the minister added.

The US, Australia, Canada, South Korea, France, Germany, Japan, Italy, the Netherlands, New Zealand, and the UK together unveiled a new plan to monitor North Korea's nuclear weapons development on Wednesday.

It came after Russia's veto at the United Nations Security Council in March triggered the end of monitoring North Korea's programme by a UN panel of experts, alarming Western states and their allies.

"Our preference would have been to continue the previous programme put in place by the Security Council. That path has been impeded by Russian intransigence," US Deputy Secretary of State Kurt Campbell told a news conference in Seoul in recent days.

"The goal of the mechanism is the full implementation of UN sanctions on North Korea by publishing information based on rigorous investigations of violations and attempts to circumvent them," the memo released by the US State Department stated.

Tensions are high after North Korea stepped up its military operations in recent months. On Wednesday it declared that it will permanently blockade the border with South Korea to counter what it called 'confrontation hysteria' on the part of South Korean and US forces.

A few hours earlier Pyongyang destroyed sections of the roads connecting the two countries. It came as an apparent response to Seoul's alleged launching of drones over the North Korean capital to distribute propaganda messages against Kim Jong-un.

And tensions between Pyongyang and Western states and their allies increased even