North Korean leader Kim Jong Un had his military chief Ri Yong Gil executed early this month on charges including corruption, Yonhap News reported, citing an unidentified source familiar with the nation's affairs.

Ri was not named after North Korea launched a long-range rocket on February 7, according to Yonhap, which added that North Korean media normally cite important officials after a major event. Both South Korea's Defense Ministry spokesman Kwon Ki-hyun and Unification Ministry spokeswoman Park Soo-jin declined to confirm the report.

Kim has purged a series of officials on charges ranging from graft to watching South Korean soap operas to bolster his grip on power since taking office in 2011, with the list including his uncle and one-time deputy, Jang Song Thaek. In January last year, he executed General Pyon In Son, head of operations in the army, for disagreeing with him; and in May he purged his defense minister Hyon Yong Chol for dozing off at a rally.

Kim was hastily groomed for leadership before the death of his father in 2011, and has sought to justify his power with adherence to his predecessor's "songun," or military-first policy. He's focused on eliminating threats to his legitimacy and has questioned even the closest aides to his family, leaving him with only a handful of seasoned advisers.

"There are two ways to look at this," Robert Kelly, professor in the department of political science and diplomacy at Pusan National University, said of the latest reported purge. "One argument is that even after nearly five years in power, Kim is still weak, and is wiping out his lieutenants to try and keep a grip. The other argument is that he's strong and is in full control of the army. He can do exactly what he wants with the army and this is a typical move to wipe out the old guard."

This story originally appeared on the New Zealand Herald.