DONALD Trump has taunted Kim Jong-un in a tweet about the rogue North Korean leader’s nuclear ambitions.

The US president spoke Saturday night with South Korean leader Moon Jae-in, pledging joint “steps to strengthen deterrence and defence capabilities and to maximise economic and diplomatic pressure on North Korea,” according to the White House.

President Trump’s own account of the conversation, which kicked off an unbridled salvo of Sunday morning tweets, struck a less diplomatic tone.

I spoke with President Moon of South Korea last night. Asked him how Rocket Man is doing. Long gas lines forming in North Korea. Too bad! — Donald J. Trump (@realDonaldTrump) September 17, 2017

“I spoke with President Moon of South Korea last night. Asked him how Rocket Man is doing. Long gas lines forming in North Korea. Too bad!” the president wrote to his 38 million followers.

He then launched into half a dozen retweets of internet memes celebrating his Make America Great Again campaign theme — topping it off with a GIF montage of himself taking a swing at a golf ball and knocking out his erstwhile Democratic rival, Hillary Clinton.

The Republican leader is set to address the United Nations General Assembly in New York for the first time on Tuesday, focusing on North Korea and Iran.

‘US HAS EXHAUSTED OPTIONS’

The US Ambassador to the United Nations, Nikki Haley, has said the UN Security Council has run out of options on containing North Korea’s nuclear program and the US may have to turn the matter over to the Pentagon.

“We have pretty much exhausted all the things that we can do at the Security Council at this point,” Ms Haley told CNN’s State of the Union on Sunday, adding that she was perfectly happy to hand the matter to Defence Secretary James Mattis.

“We’re trying every other possibility that we have but there’s a whole lot of military options on the table.”

UN Ambassador Nikki Haley on Trump’s use of Twitter: “The President can communicate in any form that he wishes” https://t.co/dpErSb5IQN — CNN (@CNN) September 17, 2017

Ms Haley also defended President Trump’s use of Twitter after he was scolded by the British prime minister over his London attack tweet.

President Trump was accused of betraying intelligence details by saying those responsible for an explosion on an underground train “are sick and demented people who were in the sights of Scotland Yard,” before adding “must be proactive!”

“You have to understand the president can communicate in any form that he wishes. And if he uses Twitter, I think what you saw was a reaction to the fact that this was terrible and we cannot let terrorist attacks become part of our normal day,” she said.

“And when you see a number of these, it makes the president more and more assured that he has to do everything he can to keep Americans safe.”

N KOREA’S THREAT MADE

Kim Jong-un has vowed to reach the country’s nuclear goals in the face of strengthening sanctions, according to state media.

The North’s official Korean Central News Agency carried Kim’s comments a day after U.S. and South Korean militaries detected the missile launch from the North Korean capital of Pyongyang.

It traveled 3,700km before landing into the northern Pacific Ocean. It was the country’s longest-ever test flight of a ballistic missile.

The North has confirmed the missile as an intermediate range Hwasong-12, which it also launched over Japan on Aug. 29.

The KCNA said Kim expressed great satisfaction over the launch, which he said verified the “combat efficiency and reliability” of the missile and the success of efforts to increase its power. While the English version of the report was less straightforward, the Korean version quoted Kim as declaring the missile as operationally ready.

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Kim also said the country, despite “limitless” international sanctions, has nearly completed the building of its nuclear weapons force and called for “all-state efforts” to reach the goal and obtain a “capacity for nuclear counterattack the U.S. cannot cope with”.

“As recognised by the whole world, we have made all these achievements despite the UN sanctions that have lasted for decades,” the agency quoted Kim as saying.

Kim said the country’s final goal is to “is to establish the equilibrium of real force with the U.S. and make the U.S. rulers dare not talk about military option for the DPRK,” referring to North Korea’s official name, the Democratic People’s Republic of Korea.

Meanwhile the North Korean newspaper Rodong Sinmun wrote the country’s weapons tests demonstrated its ability to “turn the American empire into a sea of flames through sudden surprise attack from any region and area”.