North Korea executed its top nuclear negotiators, according to report Kim Hyok-Chol, the envoy, was allegedly executed by firing squad in March.

SEOUL -- North Korea allegedly purged high-level officials after nuclear negotiations stalled between leader Kim Jong Un and President Donald Trump, according to South Korea's major newspaper ChosunIlbo.

Kim Hyok-Chol, a senior envoy who was Pyongyang's special representative for U.S. affairs, was executed at the Mirim airfield with four other officials from the Foreign Ministry in March, ChosunIlbo reported, citing a single, unidentified "source who knows about North Korea."

Kim Hyok-Chol was charged with spying for the U.S. and betraying Kim Jong Un.

The source also said Kim Yong Chol, North Korea's top nuclear negotiator, was sentenced to hard labor at a political prison camp. Kim Yong Chol had met with Trump at the White House before the Hanoi summit in February to arrange details of the negotiations.

A spokesperson at South Korea's presidential office told reporters Friday that the allegations could not be immediately confirmed.

Rumors of purges and executions in North Korea often appear on various offline and online news media outlets with the majority turning out to be false.

North Korean media in past weeks have criticized some in the regime as “turncoats,” “traitors” and “counter-revolutionaries” without specifically naming officials.

Kim Jong Un's uncle, half brother and nephew were killed off in an earlier purge.