The report on Monday came hours after President Donald Trump in a tweet urged Mr. Kim to act quickly, get the deal donewhile hinting at another summit, writing, see you soon!

North Korean leader Kim Jong Un supervised a parachuting drill of military sharpshooters and vowed to build an invincible army,displaying more defiance even as the United States and South Korea called off their own exercises to create space for nuclear diplomacy.

The report on Monday by the Korean Central News Agency came hours after President Donald Trump, in a tweet, urged Mr. Kim to act quickly and get the deal done, while hinting at another summit, writing, "See you soon!"

At an Asian defense ministers conference in Bangkok on Sunday, U.S. Defense Secretary Mark Esper said the United States has indefinitely postponed a joint military exercise with South Korea in an act of goodwill toward North Korea. Diplomats have been pushing to resume stalled nuclear talks ahead of Kim's end-of-year deadline for the Trump administration to salvage the diplomacy.

North Korea has publicised two military drill in three days. A report on Saturday said Mr. Kim urged combat pilots to prepare against enemies armed to the teeth while attending a flight demonstration.

KCNA published photos that showed Mr. Kim posing with North Korean air force sharpshooters and soldiers who used white parachutes to land on a training field.

Mr. Kim, while supervising the drill, said it necessary to wage a drill without notice under the simulated conditions of real war for improving his military war readiness and to build it into an invincible army, KNCA said. Mr. Kim did not make any specific comment towards Washington or Seoul in the report.

North Korea has been ramping up missile tests and other military demonstrations in recent months in an apparent pressure tactic over the talks.

Negotiations have faltered since a February summit between Mr. Kim and Mr. Trump in Vietnam, which broke down after the U.S. rejected North Korean demands for broad sanctions relief in exchange for a partial surrender of its nuclear capabilities.

Mr. Kim issued an end-of-year deadline for the Trump administration to offer mutually acceptable terms for a deal while saying that the North would seek a new path if the United States persists with sanctions and pressure.

Working-level talks last month in Sweden broke down over what the North Koreans described as the American rigid stance and attitude.

North Korea last week said the United States has proposed a resumption of stalled nuclear negotiations in December. But North Korean negotiator Kim Myong Gil did not clearly say whether the North would accept the supposed U.S. offer and said the country has no interest in talks if they are aimed at buying time without discussing solutions.