The nuclear threat to the Pacific has escalated dramatically with a senior Pyongyang official saying a possible hydrogen bomb test over the ocean is likely.

North Korean Foreign Ministry offical Ri Yong-pil told CNN , a previous warning of a nuclear test over the Pacific Ocean should be “taken literally”.

“The foreign minister is very well aware of the intentions of our supreme leader, so I think you should take his words literally,” Ri said in an interview that aired Thursday morning (AEST).

North Korean Foreign Minister Ri Yong-ho last month warned Pyongyang may consider conducting “the most powerful detonation” of a hydrogen bomb over the Pacific Ocean amid rising tensions with the US.

CIA chief Mike Pompeo said last week that North Korea could be only months away from gaining the ability to hit the US with nuclear weapons.

North Korea carried out the most powerful of its six nuclear tests to date last month, claiming to have used a hydrogen bomb.

The UN responded to the test by imposing harsh new sanctions on the North Korea.

North Korea’s continued threats have put its neighbours on high alert and Pyongyang launched a ballistic missile over mainland Japan last month.

Experts say an atmospheric test would be a way of demonstrating that capability. All of North Korea’s previous nuclear tests have been conducted underground.

North Korea’s ambassador, meanwhile, called on the UN Security Council on Wednesday to urgently discuss the recent US joint naval exercise near the Korean peninsula, branding it preparation for a pre-emptive strike and nuclear war against his country.

Ja Song-nam said in a letter seen by the The Associated Press that the naval exercise was the largest “waged with general mobilisation of the nuclear strategic assets” after US President Donald Trump last month “made the most ferocious declaration of war in history by claiming to ‘totally destroy’ the DPRK”.

Ja said the naval exercise, which began on October 16, increased tensions on the Korean peninsula.

The US and South Korea regularly conduct joint military exercises that Pyongyang condemns as invasion rehearsals.

“What cannot be overlooked,” the DPRK’s Ja said, “is the fact that the US, not being contented with the joint military exercise on the Korean peninsula, is kicking up the racket of military pressure upon the DPRK on a worldwide scale and is becoming more undisguised in its attempt to introduce NATO and other armed forces of its followers into the Korean peninsula in case of emergency.”

In the letter addressed to France’s UN ambassador Francois Delattre, the current Security Council president, he asked for the council to bring up the US joint military exercise as an “urgent agenda item”, saying “these military exercises constitute (a) clear threat to international peace and security.

“No other country in the world than the DPRK has ever been subjected to such an extreme and direct nuclear threat from the US for such a long time and witnessed on its door such nuclear war exercises which are the most vicious and ferocious in their scale, style, aim and essence,” the ambassador said.

– With agencies