North Korea has strongly condemned a US plan to deploy a nuclear-armed submarine near the Korean peninsula, warning of a potential devastating atomic conflict.

In a statement carried by the Korean Central News Agency (KCNA), a North Korean defence ministry spokesperson said the plan – agreed to by the US and South Korea during an April summit – would introduce US strategic nuclear weapons to the region for the first time since 1981.

The spokesperson described the move as “very dangerous”, arguing it could bring regional military tension to a critical state and could lead to the worst crisis of nuclear conflict. They added that the US plan is also an act of nuclear blackmail against North Korea and a grave threat to peace.

In response, the US has sent a nuclear-powered cruise missile submarine to the port of Busan in South Korea, as well as deploying a B-52 strategic bomber to take part in air military drills with South Korea.

North Korea has said these moves have created a “very dangerous situation” and warned of a potential “shocking incident”, citing previous incidents of North Korea shooting down or intercepting US aircraft at the border with South Korea and off the coast.

South Korean President Yoon Suk-yeol is due to attend the NATO summit in Vilnius, Lithuania, on Tuesday and Wednesday. Ahead of his departure, Yoon said he wanted to show that the international community’s determination to deter North Korea’s nuclear weapons programme is stronger than the country’s desire to develop nuclear weapons.

Yoon will be joined at the summit by the leaders of Japan, Australia and New Zealand, a sign of strengthening ties between NATO and nations in the Asia-Pacific region. He said a new NATO-South Korean document will take effect at the summit to institutionalise cooperation in 11 areas, including non-proliferation and cybersecurity.

North Korea has called the growing cooperation between NATO and US allies in Asia a process to create an “Asian version of NATO” that it believes would increase regional animosities.

Pyongyang argues its weapons-testing spree is an effort to boost defence in the face of expanded South Korean-US military drills that it views as rehearsals for invasion. Yoon, however, remains open to dialogue with North Korea.