North Korea: Kim Jong Un warns of impending nuclear warhead tests

North Korea will soon carry out a "nuclear warhead explosion test" and launch long-range ballistic missiles capable of carrying nuclear weapons, according to its leader Kim Jong Un.

His warning is seen as little more than a furious reaction by Pyongyang to annual military exercises carried out by South Korea and the United States.

State media in North Korea portrays Kim Jong Un as a heroic figure. Credit: Reuters

The state-run Korean Central News Agency said Kim issued the order while guiding a successful simulated test of a re-entry vehicle, which is needed to return a warhead safely back into the Earth's atmosphere and onto its target from a long-range missile launch.

Recent broadcasts on state media in the secretive country also claim that North Korean hydrogen bombs could "turn Manhattan to ashes", the Washington Post reports, apparently suggesting that Kim's military is now a full nuclear power with the ability to hit targets on the east coast of the US.

But many experts believe that the North does not have the technical prowess to produce a fully-working re-entry vehicle or a viable warhead capable of hitting inter-continental targets.

South Korean and US Marines take positions during an exercise Credit: Reuters

Earlier this month, North Korea ordered its nuclear arsenal to be ready for use at a moment's notice, as part of its reaction the the annual war games in its southern neighbour.

Around 17,000 American troops and more than 300,000 South Koreans took part in the military exercises, which also involved 55 US aircraft and 30 South Korean ships.

The North has denounced the exercises as "nuclear war moves" and threatened to respond with an all-out offensive involving "an ultra-precision blitzkrieg strike of the Korean style".