The visit of the USS Ronald Reagan aircraft carrier to South Korea shows that the US nuclear attack plan against North Korea has reached its "most serious stage", North Korea's state news agency KCNA said today, meaning "the risk of a nuclear war is imminent".

"It is a blatant military provocation that is escalating the situation into a catastrophic and irreversible situation," KCNA said.

The nuclear-powered aircraft carrier USS Ronald Reagan and its strike group arrived in Busan, South Korea on October 12 to join an allied exercise in a show of force against North Korea.

The United States and South Korea have held several military exercises this year, involving advanced U.S. aircraft carriers, submarines and bombers, to better respond to North Korea's growing nuclear and missile threats.

North Korea has repeatedly criticized the joint US-South Korea military exercises, viewing them as evidence of the alliance’s hostile stance and desire for regime change in Pyongyang. Washington and Seoul insist the exercises are purely defensive in nature.

KCNA said that if faced with the threat of nuclear attack, Pyongyang would take "necessary actions" mentioned in the North's nuclear doctrine, pledging to stop "the wild moves of the US and its partners to provoke a nuclear war".

"Our first swift and powerful strike will target the means of deterrence used by the US and its bases on the Korean peninsula and its vicinity," KCNA said.

Thanh Tam (According to Reuters )