US Secretary of State Mike Pompeo was scheduled to meet with Kim Jong-un last week, but the dictator stood him up in order to visit a potato farm.

Kim was conspicuously absent from the meetings in Pyongyang on Friday and Saturday, with no explanation given at the time.

But photos from state news agency KCNA showed the leader inspecting crops and getting advice to farmers.

"All the farms should not plant some species of high yield, thinking only of productivity, but introduce various species good to taste and ensure the quality of processed potato foods in production and thus raise the quality of potato production," Kim was quoted as saying.

Meanwhile, Pompeo was meeting with the comparatively junior General Kim Yong Chol.

Kim Jong-un in a potato field. (KCNA) (KCNA)

According to ABC, the general kept Pompeo waiting in an "apparent power play".

Shortly after Pompeo's departure, the North Korean foreign ministry issued a statement blasting his conduct as "unilateral and gangster-like".

Pompeo's trip "went as badly as it could have gone", a White House source told CNN.

The meeting came only weeks after Kim pledged to "denuclearise" his country at a summit in Singapore with Donald Trump.

Mike Pompeo (left) meeting with North Korean officials in Pyongyang. (AAP) (AAP)

But the agreement both signed was just a few pages long and scant on detail.

In the meantime, satellite images of a missile-manufacturing facility in the city of Hamhung showed North Korea is expanding its ballistic weapons program.

Yesterday Trump tweeted about North Korea's apparent refusal to denuclearise.

A Washington Post editorial was not kind to Trump.

North Korean dictator Kim Jong-un in a potato field. (KCNA/AAP) (KCNA/AAP)

"Kim has played Trump like a Stradivarius. He has gotten everything he wanted — sanctions relaxation, international legitimation — without giving up anything in return," columnist Max Boot wrote.

Mike Pompeo on the tarmac in Pyongyang. (AAP) (AAP)