Pyongyang bristled last week after the US president again referred to leader Kim Jong Un as ‘Rocket Man’.

A senior North Korean official called President Donald Trump a “heedless and erratic old man”, resuming insults of the American leader that were set aside during a rare thaw in relations.

Kim Yong Chol, a governing party vice chairman, launched the strongest salvo yet in a war of words that has rekindled in recent days.

He rebuked the US president over his own rhetoric and pointed to remarks by Trump on Sunday that North Korean leader Kim Jong Un had “far too much to lose”.

Those comments indicated Trump is “an old man bereft of patience”, the North Korean official said.

“The time when we cannot but call him a ‘dotard’ again may come. We have nothing more to lose,” a statement carried in state news agency KCNA quoted Kim Yong-chol as saying.

North Korea had lauded a “special relationship” between Trump and Kim even as it criticised other US officials and their “gangster-like” demands during deadlocked talks.

However, Pyongyang bristled last week after Trump again referred to Kim as “Rocket Man”, a nickname the president used early in his term.

Exchanging insults

Tensions have been rising in recent weeks as a year-end deadline, set by North Korea for Washington to soften its stance in negotiations, approaches. Pyongyang has conducted a series of weapons tests and issued strongly-worded statements.

Though Trump regularly exchanged insults with North Korea in the first years of his term, both sides abandoned personal attacks after Trump met Kim in Singapore in 2018.

Kim Yong-chol – who was instrumental in arranging a failed second Trump-Kim summit in February – said the country’s leader may change his views towards Trump if the president continues uttering “inappropriate, highly risky words and expressions”.

On Sunday, North Korea carried out what it called a “very important” test at its Sohae satellite launching station, a rocket-testing ground that US and South Korean officials once said Pyongyang had promised to shut down.

Commercial satellite images taken on Saturday by Planet Labs showed vehicles and equipment likely to be used in a rocket engine experiment, said Jeffrey Lewis, the director of the East Asia Nonproliferation Program at the Middlebury Institute of International Studies in California.

“They are mostly gone on December 8 but the ground appears to have been disturbed by the exhaust from the test,” Lewis said, citing photo imagery.

Asked on Monday if it had been an engine test, a spokeswoman for South Korea‘s defence ministry said site monitoring and detailed analyses were under way with US intelligence authorities.

Kim has warned he might take a “new path” if the United States fails to address his demands.

Observers have said that path might include the launch of a space satellite, which would help North Korea demonstrate progress in its rocket capabilities without returning to overt military provocations such as firing an intercontinental ballistic missile (ICBM).

Kim Yong-chol, the North Korean official, said Trump should try to “stop the second-hand” of a clock ticking towards conflict, instead of sticking to “bluffing and hypocrisy that sound rather abnormal and unrealistic”.

“We have no intention to reconsider what we should do in the future, and will not feel worried about our future action,” he said in the English-language dispatch on KCNA.

Some South Korean analysts said North Korea might have tested a solid-fuel rocket engine, which could allow it to field ICBMs that are easier to hide and faster to deploy.

“They may well have tried to see the thrust and duration of a solid-propellant rocket engine for ICBMs,” a diplomatic source in Seoul told Reuters news agency. “That’s effectively what they can do on the ground at this point without firing anything into the air.”