The United States has warned the North Korea leadership that it will be “utterly destroyed” if war breaks out, after Pyongyang test fired its most advanced intercontinental ballistic missile, putting the US mainland within range.

The Trump administration has repeatedly said all options are on the table in dealing with North Korea’s ballistic and nuclear weapons program, including military ones, but that it still prefers a diplomatic option.

Still, speaking at an emergency UN Security Council meeting, US ambassador Nikki Haley warned:

“We have never sought war with North Korea, and still today we do not seek it,” Ms Haley said.

“If war does come, it will be because of continued acts of aggression like we witnessed yesterday … And if war comes, make no mistake, the North Korean regime will be utterly destroyed.”

Ms Haley said the US has asked China to cut off oil supply to North Korea, a drastic step that Beijing – the North’s sole major trading partner – has so far refrained from doing.

Mr Trump spoke with Chinese President Xi Jinping earlier on Wednesday and said more sanctions on Pyongyang would be enforced. 

Ms Haley said the US has never sought war with North Korea. Photo: Getty

“Just spoke to President Xi Jinping of China concerning the provocative actions of North Korea. Additional major sanctions will be imposed on North Korea today. This situation will be handled!” the President wrote on Twitter.

In a speech in Missouri about taxes, Mr Trump, who has traded insults with the North in the past, referred to Kim Jong-un with a derisive nickname.

“Little Rocket Man. He is a sick puppy,” Mr Trump said.

North Korea, which conducted its sixth and largest nuclear bomb test in September, has tested dozens of ballistic missiles under Kim’s leadership in defiance of international sanctions.

North Korea said the new missile soared to an altitude of about 4,475 km – more than 10 times the height of the International Space Station – and flew 950 km during its 53-minute flight.

It flew higher and longer than any North Korean missile before, landing in the sea near Japan. Experts said the new “Hwasong-15” missile theoretically gave North Korea the ability to hit the United States, including the East Coast, although it was not clear whether it could carry a nuclear weapon.

The latest missile was fired a week after Mr Trump put North Korea back on a US list of countries it says support terrorism, allowing it to impose more sanctions.

Kim personally guided the test and described it as “impeccable”, state media said.

North Korea also described itself as a “responsible nuclear power”, saying its strategic weapons were developed to defend itself from “the US imperialists’ nuclear blackmail policy and nuclear threat”.