Five North Korean official were executed with a burst of anti-aircraft guns in the capital Pyongyang last week for providing false information to their leader Kim Jong Un.
The South Korea's National Intelligence Service (NIS) said in a private briefing to lawmakers, while Malaysia is investigates the poisoning death of Kim's estranged elder half brother, Kim Jong Nam.
Though the investigation is still going on, South Korea says it believes Kim Jong Un ordered the assassination, which took place Feb. 13 at Kuala Lumpur's airport.
The spy agency told lawmakers that five North Korean officials in the department of recently purged state security chief Kim Won Hong were executed by anti-aircraft guns because of the false reports to Kim, South Korean lawmaker Lee Cheol Woo said.
It's unclear what false reports they allegedly made.
South Korean spies have a spotty record when reporting about high-level events in authoritarian, cloistered North Korea.
North Korea fired Kim Won Hong in January, presumably over corruption, abuse of power and torture committed by his agency, Seoul said earlier this month. The fallen minister had been seen as close to Kim Jong Un.
North Korea has not publicly said anything about Kim Won Hong or about the alleged executions in his department.
Lawmaker Lee also cited the NIS as saying that Kim Won Hong's dismissal was linked to those false reports, which "enraged" Kim Jong Un when they were discovered.
Since taking power in late 2011, Kim Jong Un has reportedly executed or purged a large number of high-level government officials. Seoul has called it as "reign of terror."