United States Secretary of Defence James Mattis once again threatened North Korea Saturday with a “massive military response” should Pyongyang attack his country or its allies.

Speaking a day after visiting the Demilitarised Zone that separates the Koreas, Mattis reemphasised that a diplomatic solution remains Washington’s preference – but added that his country also has many military options.

Mattis’ second trip to South Korea this year comes less than a fortnight ahead of President Donald Trump’s own state visit to the peninsula and just two months after North Korea’s sixth ever nuclear test.

“Our diplomats are most effective when backed by credible military force in this sort of situation,” the American defense chief insisted at a joint press conference with his South Korean counterpart Song Young-moo.

“Make no mistake – any attack on the United States or our allies, will be defeated,” Mattis was quoted as saying by local news agency Yonhap. “Any use of nuclear weapons will be met with a massive military response.”

He added that he “cannot imagine a condition under which the United States can accept North Korea as a nuclear power.”

Pyongyang has continued to carry out nuclear weapon tests this year in defiance of United Nations resolutions aimed at denuclearising the reclusive nation.

The North sees nuclear weapons as a sovereign right to self-defence in the face of nearly 30,000 American troops stationed in South Korea along with regional strategic assets. (Anadolu Agency)