New American defence chief Jim ‘Mad Dog’ Mattis warns North Korea of ‘overwhelming’ retaliation strikes if Kim dares to launch nukes

THE new US Defence Secretary warned crackpot Kim Jong-Un he faces an "overwhelming" response if North Korea uses nuclear weapons.

Jim 'Mad Dog' Mattis sent a no-holds-barred threat to the dictator on a visit to neighbouring South Korea.

He warned: "Any attack on the United States, or our allies, will be defeated.

"And any use of nuclear weapons would be met with a response that would be effective and overwhelming."

Mattis was responding to fears North Korea is close to developing a ballistic missile capable of carrying nuclear warheads.

The hi-tech missiles  - with a range of more than 6,000 miles - are thought to be capable of striking targets in America.

Kim's secretive regime has carried out underground nuclear tests for more than a decade but was previously thought to be unable to fit its bombs to accurate rockets.

Firing another warning, Mattis added: "North Korea continues to launch missiles, develop its nuclear weapons program and engage in threatening rhetoric and behaviour."

Mattis met Japanese Prime Minister Shinzo Abe today - another ally strongly opposed to Kim's regime.

Donald Trump vowed to stop the North Koreans building a nuclear weapon capable of reaching the US last month.

The new president tweeted: "North Korea just stated that it is in the final stages of developing a nuclear weapon capable of reaching parts of the US It won’t happen!”

And newly-appointed Mattis similarly called the communist state's weapons programme "a serious threat" and vowed to "do something about it".

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