NORTH Korea could have material for 20 NUCLEAR bombs by the end of this year experts have revealed as the defiant South threatens annihilation if one missile is fired towards it.

The secretive state detonated a nuclear bomb “twice of the size of Hiroshima” last week and announced it could produce more warheads “any time we desire”.

7 The international community has condemned tubby tyrant Kim Jong-un's 'maniacal nuclear test' Credit: Reuters

7 A man watches a television screen reporting news of a North Korea submarine-launched ballistic missile test Credit: Getty Images

Friday's explosion was the fifth and biggest test carried out since dictator Kim Jong-un came to power in 2011.

In response South Korean president Park Geun-hye vowed it would annihilate the state the "very second the North fires even one nuke at us".

She has also pledged to continue the construction of a nuclear shield, which it is hoped would shoot down missiles before they reached the South.

Just days before the test South Korean military forces warned they will destroy the North’s capital with "ballistic missiles and high-explosives" if they detected any sign of a nuclear attack.

7 Picture of a missile test released by North Korea's official Korean Central News Agency Credit: Getty Images

7 Protests against North Korean leader Kim Jong-un's nuclear tests have been held in South Korea Credit: AP:Associated Press

7 North Korean leader Kim Jong-un celebrates a previous missile test

A military source told Yonhap news agency, which has strong ties to South Korea’s government, that the North’s leadership would be specifically targeted, with Pyongyang "reduced to ashes and removed from the map".

An expert has said Kim Jong-un has expanded his uranium enrichment facilities, which combined with stockpiled plutonium could create enough material for 20 nuclear weapons.

Last week's test, held in underground tunnels at the Punggye-ri nuclear test site, was the second this year.

Double-chinned dictator Kim Jong-un has ignored UN sanctions for years and experts have consistently said it is impossible to know exactly what nuclear capabilities North Korea has.

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But, Siegfried Hecker, a leading expert on North Korea's nuclear programme has assessed evidence of the country's capabilities and made chilling conclusions.

He said the country has enough plutonium stockpiled for six to eight bombs - on top of this he believes it can produce enough plutonium for one more bomb each year.

Based on evidence seen during a visit to Yongbyon centrifuge facility - North Korea's nuclear facility - in 2010, he also believes the state could add another six bombs to this total.

In a report published on 38 North website of the Johns Hopkins University in Washington on Monday he said: "A stockpile of sufficient fissile material for approximately 20 bombs by the end of this year and a capacity of adding approximately seven per year makes the DPRK claim sound plausible."

On top of this the American nuclear scientist suggests the country could develop long range missiles - capable of reaching the US - in five to 10 years, if the program is unconstrained.

7 South Korean President Park Geun-hye has said the north will be annihilated if it fires a missile towards the south Credit: AP:Associated Press

7 Buildings in the square were also decorated with Kim Jong-un's party flag Credit: Reuters

This week the state held a creepy Nazi style mass rally to celebrate the country's fifth nuclear test.

Footage broadcast on state media showed thousands of residents clapping in unison as party leaders watched from the balcony.

World leaders have slammed Kim Jong-un's behaviour as "maniacal recklessness".

After the North Korea's test last Friday, British Foreign Secretary Boris Johnson said: “These reports are of grave concern. The United Kingdom strongly condemns North Korea for conducting a further nuclear test, which is a flagrant violation of UN Security Council Resolutions and a threat to regional peace and stability.

“Together with the Australian Foreign Minister I have spoken this morning to the Japanese Foreign Minister, and the UK will be consulting other international partners on a robust response.”

The Sun Online exclusively reported on Saturday that the reclusive nation hosted a bizarre trade show to raise money to make bombs.

The 12th Pyongyang Autumn International Trade Fair, which opened at the Three-Revolution Exhibition House, in Pyongyang, on Monday, saw stalls selling budget laptops, tablets, Coca Cola copy-cats and other food items, basketballs, fur garments, scooters and even massage chairs.

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