A man walks past in front of TV screen showing North Korean leader Kim Jong Un in Tokyo, Monday, Dec. 9, 2019. North Korea said Sunday that it carried out a "very important test" at its long-range rocket launch site that it reportedly rebuilt after having partially dismantled it at the start of denuclearization talks with the United States last year.

SEOUL, South Korea – North Korea insulted U.S. President Donald Trump again on Monday, calling him a “thoughtless and sneaky old man” after he tweeted that North Korean leader Kim Jong Un wouldn’t want to abandon a special relationship between the two leaders and affect the American presidential election by resuming hostile acts.

A senior North Korean official, former nuclear negotiator Kim Yong Chol, said in a statement that his country wouldn’t cave in to U.S. pressure because it has nothing to lose and accused the Trump administration of attempting to buy time ahead of an end-of-year deadline set by Kim Jong Un for Washington to salvage nuclear talks.

Nuclear negotiations faltered after a February summit between Trump and Kim Jong Un in Vietnam broke down when the U.S. side rejected North Korean demands for broad sanctions relief in exchange for a partial surrender of its nuclear capabilities.

Kim has said North Korea will seek a “new way” if the U.S. maintains its sanctions and pressure, and issued the deadline for the Trump administration to offer mutually acceptable terms for a deal.

More:Trump warns North Korea's Kim Jong Un not to put their 'special relationship' at risk with 'hostile' acts