A close aide to North Korean leader Kim Jong Un on Thursday lambasted U.S. President Donald Trump for calling him a "Rocket Man" again, saying it represents a "very dangerous challenge."

"What makes us feel further worse is that the figurative style was dare used at random with no courtesy when referring to the supreme leadership of dignity of the DPRK," First Vice Foreign Minister Choe Son Hu said in a statement carried by the official Korean Central News Agency in English.

DPRK is the acronym for North Korea's official name, the Democratic People's Republic of Korea.

Earlier this week, Trump told reporters in London that Kim "likes sending rockets, doesn't he? That's why I call him Rocket Man," hinting at using his country's military might against North Korea if necessary.

Since earlier this year, North Korea has carried out test-firings of what appeared to be short-range ballistic missiles in defiance of U.N. Security Council resolutions banning it from developing ballistic missiles and nuclear weapons.

"It would be fortunate if the utterances of the use of military force and the title of figurative style made by President Trump were an instantaneous verbal lapse, but matter becomes different if they were a planned provocation that deliberately targeted us," Choe said.

"If this is meant to make expressions, reminiscent of those days just two years ago when a war of words was fought across the ocean, surface again on purpose, it will be a very dangerous challenge," she added.

In his speech to the United Nations in September 2017, Trump said he is prepared to "totally destroy" North Korea if the United States is forced to defend itself or its allies. He also mocked the North Korean leader as "Rocket Man."

Kim responded then by issuing a statement saying, "Now that Trump has...insulted me and my country in front of the eyes of the world...we will consider with seriousness exercising of a corresponding, highest level of hard-line countermeasure in history."

At that time, North Korean officials subsequently suggested the nation could test a powerful hydrogen bomb over the Pacific Ocean.

In April 2018, North Korea formally decided to "discontinue nuclear test and intercontinental ballistic rocket" test-firings as well as "concentrate all efforts on building a powerful socialist economy."

North Korea, however, has recently warned that it will resume nuclear and intercontinental ballistic missile tests, should negotiations with the United States over denuclearization fail to achieve a breakthrough by the end of the year.

The United States and North Korea technically remain in a state of war after the 1950-1953 Korean War ended in a cease-fire. The two countries do not maintain diplomatic relations.

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