North Korea's leader Kim Jong-Un has named Hyon Yong Chol as his new military chief, the state news agency has said.
Mr Hyon replaces Vice Marshall Ri Yong Hon who was dismissed from several powerful posts due to illness on Monday.
The surprise announcement came just days after he last appeared in public, where he did not appear to be unwell.
The move has fuelled speculation abroad that Kim Jong-Un removed him from his numerous posts to stamp his own mark on the nation he inherited from his father Kim Jong-Il in December.
On Tuesday the official Korean Central News Agency announced that the title of vice marshall had been bestowed on Mr Hyon. No details were provided about him or his military background.
It was not immediately clear if he would receive any of Mr Ri's other titles and powers, including chief of the General Staff of the Korean People's Army.
The appointment was made by the Central Military Commission of the Workers' Party of Korea and the National Defense Commission of North Korea, the agency said.
Daniel Pinkston, a North Korea analyst at the International Crisis Group, was sceptical of the illness claim surrounding Mr Ri. He noted that he had won his major promotions at a September 2010 party conference but received none in April, stirring speculation about his future.
"There's a very high probability that it wasn't health issues, but that he was purged," sending a strong signal to anyone seeking to challenge Kim Jong-Un - even if Mr Ri never directly defied the new leader, Mr Pinkston said.
Mr Ri was shown in photos as recently as July 6 chatting with Pyongyang residents and two days later he joined Kim Jong-Un at the Kumsusan mausoleum to pay respects to Kim Il-Sung.
Where Mr Ri's departure leaves North Korea's million-man army, one of the world's largest, remained unanswered.
The dismissal comes as Mr Kim makes waves in other ways. State TV showed him appearing at a music concert and visiting a school recently in the company of a mysterious woman who carried herself much like a first lady.
Her identity has not been revealed but her public presence was a notable change from Kim Jong-Il's era, when his companions were kept out of state media.