President Trump’s “Rocket Man” nickname appears to have hit a sore spot -- again.

North Korea warned Thursday that it may start calling the U.S. leader a “dotard” again if he continues to refer to Kim Jong Un with the moniker.

Choe Son Hui, the first vice foreign minister, was the one who launched the hermit kingdom’s latest salvo against the U.S., days after Trump talked about possible military action toward the North if Kim doesn’t follow up on a commitment to denuclearize.

“If any language and expressions stoking the atmosphere of confrontation are used once again on purpose at a crucial moment as now, that must really be diagnosed as the relapse of the dotage of a dotard,” Choe said in a warning issued through state media.

In this June 30 file photo, President Trump, left, meets with North Korean leader Kim Jong Un at the North Korean side of the border at the village of Panmunjom in Demilitarized Zone. (AP)

KIM JONG UN PICTURED RIDING WHITE HORSE TOWARD SACRED MOUNTAIN

In recent months, North Korea has hinted at lifting its moratorium on nuclear and long-range missile tests if the Trump administration fails to make substantial concessions in nuclear diplomacy before the end of the year.

On Tuesday, during a visit to London, Trump said his relationship with Kim was “really good” but also called for him to denuclearize.

“We have the most powerful military we ever had, and we are by far the most powerful country in the world and hopefully we don’t have to use it,” Trump added. “But if we do, we will use it.”

Trump also remarked that Kim “definitely likes sending rockets up, doesn’t he?”

“That’s why I call him ‘Rocket Man’,” Trump said.

In this Feb. 28 file photo, North Korea Deputy Foreign Minister Choe Son Hui talks during a press conference at Melia Hotel in Hanoi, Vietnam. (AP)

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Choe said Trump’s remarks “prompted the waves of hatred of our people against the U.S.” because they showed “no courtesy when referring to the supreme leadership of dignity” of North Korea.

She added that North Korea will respond with its own harsh language if Trump again uses similar phrases and shows that he is intentionally provoking Pyongyang.

On Wednesday, the North’s military chief, Pak Jong Chon, also warned that the use of force against the North would cause a “horrible” consequence for the Americans. He said North Korea will take unspecified “prompt corresponding actions at any level” if the U.S. takes any military action.

In 2017, Trump and Kim traded threats of destruction as North Korea carried out a slew of high-profile weapons tests aimed at acquiring an ability to launch nuclear strikes on the U.S. mainland. Trump said he would rain “fire and fury” on North Korea and derided Kim as “little rocket man,” while Kim questioned Trump’s sanity and said he would "tame the mentally deranged U.S. dotard with fire.”

This undated photo provided on Wednesday by the North Korean government shows North Korean leader Kim Jong Un, center, with his wife Ri Sol Ju, right, riding on white horse during his visit to Mount Paektu, North Korea. (AP/Korean Central News Agency)

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The two leaders have avoided such words and developed better relations after North Korea entered nuclear negotiations with the U.S. last year. Trump even said he and Kim “fell in love.”

Kim and Trump have met three times, starting with a summit in Singapore in June last year. But their nuclear diplomacy has remained largely deadlocked since their second meeting in Vietnam in February ended without any deal due to disputes over U.S.-led sanctions on North Korea.

The Associated Press contributed to this report.