Several senior commanders have been either disappeared from their posts or have been sent for “re-revolutionisation education”, South Korean intelligence agents say.
But analysts have warned the shake-up at the top of the powerful politburo may only serve to harden the army’s resistance to Kim’s leadership.
And as international sanctions continue to strangle North Korea’s oil and fuel supplies, unrest in the ranks is likely to continue to grow.
South Korea’s National Intelligence Service (NIS) has now briefed officials in Seoul about the change in leadership of the politburo, formally the Political Bureau of the Workers’ Party of Korea.
And in their report, the spy agency said Kim has been exploring ways to bring the “unruly” military to order.
General Hwang Pyong-so had served as the head of the politburo, and was part of Kim’s inner circle until he disappeared from public in October.
Three other senior officers have also either been removed from their posts or sent for re-education at one of the North’s political prison camps.
Daniel Pinkston, a professor of international relations at the Seoul campus of Troy University, said: “Purges and the demotion of senior politicians and generals happens quite frequently in the North and is used to tighten discipline and to keep the military in check.
“We may never know the real reasons, but these punishments may be for some kind of indiscretion or behaviour that is viewed as unacceptable.
“With four senior people, maybe it was some form of collusion or concern about some kind of counterrevolutionary plot.”
General Hwang was frequently photographed standing next to Kim at major events such as military parades and missile tests.
However, he has not been pictured for months, prompting speculation he has been executed or imprisoned.
The NIS report states Hwang had been in a power struggle with Choe Ryong-hae, Kim’s right hand man.
The intelligence suggests Choe used his position to launch a probe into senior figures in the army, which is said to be the first such investigation in more than 20 years.
Toshimitsu Shigemura, a professor at Tokyo’s Waseda University and an authority on North Korea’s ruling family, said Kim’s decision to switch from a ‘military first’ policy to a ’party first’ stance has angered the armed forces, who he said have gotten “used to having everything their own way.”
He said: “Since he changed the priority to the party, Mr Kim has been afraid of a coup instigated by the military, so he is doing everything in his power to exert control over their leaders and making sure they are not strong enough to challenge his authority.”