North Korea on Saturday released a video threatening a nuclear strike on Washington if provoked.

Titled "Last Chance", the four-minute clip shows a montage of the turbulent history between the USA and the reclusive Communist state, before a nuclear bomb comes bursting through clouds and slams into the iconic Lincoln Memorial.

A message on the screen in Korean said North Korea would hit the U.S. with nukes if the American imperialists moved an inch towards it. The repressive North Korean regime has upped its war of words lately as the USA and South Korea hold large-scale war games that Pyongyang considers a prelude to war.North Korea is not known for subtlety.

It is the latest in a series of threats against Washington and Seoul following the start of joint military drills by the United States and South Korea.

Kim Jin-moo of the Korea Institute for Defense Analyses, South Korea's state-run research institute, speculated that the timing of the fifth nuclear test could be tied to the opening of North Korea's ruling party gathering in early May. Pyongyang denies responsibility for the torpedoing that occurred when the same South Korea-U.S. drills were under way, though it acknowledged bombarding the island.

A defector from the North previously told Reuters that Kim was a Christian pastor who had worked in China and the United States and sent medical aid into the North.

Others are refraining from a definitive response and said assuming North Korea has the capability is not conclusive since they have "not demonstrated" its capacity, according to Pentagon Press Secretary Peter Cook.

North Korea tested its first nuclear weapon in 2006 but was believed to be a long way from being able to miniaturise a device to fit on a ballistic missile.

It has conducted a number of what it says were successful tests of an SLBM, but experts have questioned the claim, suggesting Pyongyang had gone little further than a "pop-up" test from a submerged platform.

On Friday, South Korean President Park Geun-hye gave a speech in Seoul condemning North Korea, saying it continues to engage in "provocations" that South Korea will not accept.

Hatred for America has become a staple in the North Korean political world that has increased as the repressive regime has begun to develop nuclear weapons.

North Korea has held similar events previously in which prisoners made statements that appeared to be pre-vetted by authorities.