North Korea has named a new army vice marshal, state media said Tuesday, as part of a reshuffle apparently aimed at tightening young leader Kim Jong-Un's grip on the communist state's powerful military.

Hyon Yong-Chol, a veteran field commander, is now one of four people in the North to hold the rank of vice marshal of the Korean People's Army, and analysts say he is likely to become head of the 1.2-million-strong military.

Ri Yong-Ho, the chief of the general staff, was relieved of all his posts on Sunday due to "illness" amid widespread scepticism over the official reason given for his departure.

"A decision on awarding the title was made by the Central Military Commission of the Workers' Party of Korea and the National Defence Commission of (North Korea) on Monday," Pyongyang's official Korean Central News Agency (KCNA) said.

Little is known about Hyon, who is in his early 60s, but he is believed to be from a family who fought alongside North Korea's founding father Kim Il-Sung against Japanese forces during the colonial era.

He became a general in September 2010 along with five others -- including Kim Jong-Un himself and his aunt Kim Kyong-Hui.

"Hyon is expected to succeed Ri Yong-Ho (as head of the military)," Professor Yang Moo-Jin of the University of North Korean Studies in Seoul told AFP.

Hyon is also likely to take over Ri's other key posts, becoming a member of the political bureau presidium, the party's highest body with a handful of members, and vice-chairman of the central military commission, analysts said.

Cheong Seong-Chang, of the Sejong Institute, said the apparent move to replace Ri with Hyon showed the young leader was reinforcing his control over the military.

But unlike Ri, who has been a highly visible supporter of Kim following the death of his father Kim Jong-Il in December, Hyon has not accompanied the new leader during his public appearances.

Daniel Pinkston, Northeast Asia deputy project director at the International Crisis Group, said senior officials like Ri have "opportunities to earn windfall profits" and he "may have been purged for corruption".

Pinkston said Ri may have also landed in trouble because of his son who is the head of the so-called Ponghwajo, a social group involving the sons of high-ranking officials who are reportedly often engaged in criminal activity.

Other analysts said Ri's fall from power was inevitable after Choe Ryong-Hae, a civilian party official, became director of the general political bureau, the military's top political commissar.

Despite having little military experience, Choe was also appointed as a vice marshal, and he was made one of the two vice chairmen -- alongside Ri -- of the central military commission, which is chaired by Kim.

"This is all part of Jong-Un's move to tame the military," Yoo Dong-Ryul, senior researcher at the state Police Science Institute, told AFP.

"Ri must have resented Choe's assuming control over the military and his complaints reached Jong-Un's ears".

The North's military has in recent months ratcheted up hostile rhetoric towards South Korea and its President Lee Myung-Bak, partly in a bid to burnish Jong-Un's credentials.

Ri, at a massive anti-Seoul rally in Pyongyang in March, called South Korean leaders "mad dogs" and "psychos" and declared a "sacred war" against Seoul for allegedly insulting the North's leadership.

The impoverished but nuclear-armed North last month also denounced US-South Korean drills near the tense border as a provocation and vowed to bolster its "nuclear deterrent".

It was the latest sign of high tensions after the North's failed rocket launch in April, seen by the United States and its allies as an attempted ballistic missile test.