A top North Korean military officer was executed earlier this month on charges of pursuing personal interests and engaging in corruption, a source said Wednesday.

The source said that the execution of Ri Yong-gil, the chief of the General Staff of the North’s Korean People’s Army, occurred around the time a senior-level meeting involving officials from the military and the ruling Workers’ Party was convened from Feb. 2-3.

The execution came as a surprise, as Ri had been regarded as one of the most prominent figures in the Kim coterie. In 2013, Ri was appointed as the general staff chief equivalent to South Korea’s Joint Chiefs of Staff chairman. The next year, he become a candidate member of the party’s powerful politburo.

The source offered several potential reasons for his execution.

“Recently, North Korean leader Kim appointed party officials for senior military posts. For this, Ri, a longtime active-duty field officer, might have expressed his displeasure,” the source told reporters.

“There is also a possibility that those who lead party control over the military might have reported Ri’s (concocted) blasphemous activities to the authorities so as to eliminate him.”

The sources also noted that the continued executions of top military officers signaled that Kim was apprehensive about maintaining firm control over the North’s military.

Since Kim took power in December 2011, a series of top military officers were purged or executed. In July 2012, Ri Yong-ho, then chief of the general staff of the North’s military, was purged. Ri was then replaced by Hyon Yong-chol, who was executed in April 2015.

Rumors have persisted that there could be some power struggle between military and party officials as Kim has been trying to strengthen the role of the party as part of efforts to institutionalize his dictatorship. Under the rule of his late father Kim Jong-il, the party’s role to support the leader was rather loose, as he wielded enormous charismatic authority.

Speculation about Ri’s oust had already been circulating as he had not appeared at recent high-profile military events including a Pyongyang ceremony marking what the reclusive regime claims to be a successful launch of the Kwangmyongsong-4 satellite.

Reporting on the ceremony for the satellite launch, the Rodong Sinmun, the daily of the ruling party, enumerated participants in the order of their military and party rankings. Ri Myong-su, an general of the North’s Korean People’s Army, took the place of the executed Ri, sparking speculation that he might have been newly appointed for the general staff chief post.

By Song Sang-ho (sshluck@heraldcorp.com)