South Korean newspaper Chosun Ilbo reported that Kim Kyok Chol was one of five officials in North Korea's foreign ministry to be killed in March.

Kim Kyok Chol was reportedly executed after the failed summit in Hanoi. (AP)

His execution came soon after both Kim Jong-un and President Trump left the February summit in Vietnam without an agreement.

A North Korean source said the special envoy was "investigated and executed at Mirim Airport".

Donald Trump's summit with Kim Jong-un was a failure. (AAP)

Another of the dictator's aides, Kim Yong Chol, is currently serving hard labour.

And Kim Jong-un's translator at the summit, Shin Hye Yong, is also in a political prison camp for making a critical interpretation mistake.

The meeting between Trump and Kim in Hanoi was widely seen as an embarrassing failure, with both parties leaving early.

Negotiations between the two countries have stalled, and North Korea has begun its weapons testing programs again.

According to Chosun Ilbo Kim was believed to be carrying out a widespread purge to divert attention from internal turmoil and discontent.

Kim Jong-un has launched a purge of his foreign ministry, including the execution of five officials. (AAP)

“Kim Hyok-chol was investigated and executed at Mirim airport with four foreign ministry officials in March,” an unnamed North Korea source said, according to the Chosun Ilbo, adding that they were charged with spying for the United States.

Earlier this month North Korea launched several short-range missiles.

On Sunday Mr Trump expressed his faith in Kim via Twitter.

Purges of political officials in North Korea are disturbingly common.

In 2013, Kim's uncle-in-law Jang Song-thaek was executed after he pushed for reform within the country.

His two top deputies were also killed, shot with anti-aircraft machine guns.

Kim's brother Kim Jong-nam was assassinated in Malaysia in 2017 using a nerve agent.

It was also widely reported that Kim ordered the execution of the architect of a new airport because he did not approve of the design.

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However it is worth noting that South Korea media and intelligence have made mistakes in the past, wrongly revealing one of Kim's former military chiefs was dead.

In 2016, Ri Yong-gil was alive and in possession of several new senior-level posts after the South incorrectly reported he had earlier been executed.

Seoul intelligence officials claimed Kim had him executed for corruption and other charges.

Ri, a trusted member of Kim's inner circle, was among those awarded important positions during the just concluded Workers' Party congress in Pyongyang.

According to John Blaxland, Professor of International Security and Intelligence Studies and director of ANU's Southeast Asia Institute, the execution sent a clear message that Kim Jong-un and the North Korean regime have not changed.

"Chol may have been close to Kim Jong-un, but I would have thought he was quite close to his half-brother (Kim Jong-nam) whom he had killed in Malaysia as well, so the level of closeness offers no guarantee of protection in his circle," he said.