North Korea's top military leader, and a key mentor to leader Kim Jong-Un, has been removed from all posts due to illness, state media has reported.
Ri Yong Ho has been at the young leader's side since he succeeded his father Kim Jong-Il in 2010.
But it has been suggested that the reason for his sudden departure could be Mr Kim's desire to put his own mark on the government he inherited.
The decision to relieve Mr Ri of his duties was made at a Workers' Party meeting on Sunday, according to the North's official Korean Central News Agency.
It was not immediately clear who would take his place and the agency did not elaborate on Mr Ri's condition or future.
Mr Ri was vice marshall of the Korean People's Army and the military's General Staff chief, as well as a top figure in the Workers' Party.
Hong Hyun-ik, an analyst at the Sejong Institute near Seoul, was sceptical about the illness claim, saying that when top North Korean officials do get sick, they typically remain in office while deputies handle their duties. There had been no previous sign that Mr Ri was ill, he added.
Mr Hong said the change appears aimed at replacing an appointee of Mr Kim's late father with a closer confidant.
"It can be seen as part of a general change," Mr Hong said, adding that he expects similar news on the dismissal of other aging, senior officials will come out in coming weeks.
Animosity on the Korean Peninsula has deepened since a North Korean rocket launch in April that the UN called a cover for a banned long-range missile test. North Korea said it was a satellite launch.
North Korea has repeatedly threatened harm to South Korea's president and his supporters in recent months, angry over perceived insults to its leadership and recent US-South Korean military drills that Pyongyang says are a prelude to an invasion.