North Korean leader Kim Jong-Un has pushed out a high-profile military figure, who once played a key role under his late father -- the latest in a series of top-level personnel changes. The Korean Central News Agency (KCNA) identified a new figure, Jon Chang-Bok, as first vice-minister of the People's Armed Forces Ministry in a report Thursday which detailed Kim's trip to an army food-processing factory. The People's Armed Forces Ministry is essentially the defence ministry and comes under the control of the powerful National Defence Commission. KCNA did not say when Jon, a relatively little-known figure, was appointed to the post, but he replaces Vice Marshal Hyon Chol-Hae. Hyon, 79, was regarded as one of the North's top military figures who helped support the young leader following the death of his father, Kim Jong-Il, in December 2011. But Kim Jong-Un has reshuffled his military top brass in an apparent attempt to secure his leadership since taking over the reins of power. In changes disclosed on Sunday, Jang Jong-Nam, a relatively young field commander believed to be in his mid-50s, replaced hawkish defence minister Kim Kyok-Sik. Kim Kyok-Sik, appointed six months ago, had been seen as a hardline choice given that he was widely believed to have directed the 2010 shelling of a South Korean border island. Jang, who will now have Jon as his number-two, is not the most senior figure in the Korean military. The National Defence Commission is chaired by Kim Jong-Un as supreme commander. Despite the shake-up, other old-guard figures remain in influential positions in the commission and other leadership bodies. The changes come as the Korean peninsula emerges from a period of highly-elevated military tensions that followed the North's nuclear test in February.