North Korea says it will never give up its nuclear weapons as long as the United States and its allies continue their "blackmail and war drills" at its doorstep.

The North's official Korean Central News Agency took the oft-repeated stance on Saturday as it reviewed the country's major nuclear weapons and missile tests this year.

North Korea conducted its most powerful nuclear test to date in September and launched three different intercontinental ballistic missiles into the sea in July and November, raising fears that it is closer than ever to gaining a nuclear arsenal that could viably target the United States.

KCNA said North Korea's "entity as an invincible power can neither be undermined nor be stamped out."