It was latest case in the reign of terror that has marked the governance of Kim, who came to power in his early 30s after his father Kim Jong-il's sudden death in 2011.

Issuing a report on the latest purge, senior researcher Kwak Gil-sub at the Seoul-based institute said "the instability under the Kim Jong-un regime is likely to escalate in the course of time." 

The action taken against the former spy chief, who had been instrumental in executing Kim's reign of terror, is intended to solidify the leader's supremacy and similarly designed purges may further accelerate down the road, Kwak predicted. 

"Kim Wong-hong's purge may appear to be temporarily helpful for Kim Jong-un's efforts to rein in the elite class, but in the long-term it will serve as a critical moment in instilling the notion that Kim Jong-un regards even his closest aides as disposable," the researcher said.    

On the surface, the recent purge has been attributed to corruption, abuse of power and the defection of former North Korean diplomat in London Thae Yong-ho, but in fact it was the result of a power game among key government bodies and Kim's royalist groups, he also noted.  

Following the purge, North Korea's elite class may try to look more allegiant to Kim, but behind the scenes, they will be pointing a finger at Kim, he added. (Yonhap)