Seoul: North Korean media on Saturday hailed the youngest son of late leader Kim Jong-Il as ‘supreme commander’ of the powerful military, in the latest sign that the untested successor is cementing his hold on power.

"We will uphold Comrade Kim Jong-Un as our supreme commander and general and we will bring the Songun (military-first) revolution to a completion," the ruling communist party's Rodong Sinmun said in an editorial.

It is the first time that one of the North's mouthpieces has used the title supreme commander -- a post previously held by his father -- for the new leader, already a four-star general though still in his late 20s.

"This shows that Jong-Un now has a firm grip on the military and the North is heralding this to the outside world," Professor Kim Yong-Hyun of Dongguk University in Seoul told a news agency.

"It also suggests that the North will continue with its Songun policy at least in the foreseeable future."

North Korea on Monday described the untested Jong-Un as the ‘great successor’ after announcing the death of his father at age 69.

The latest acclamation is particularly significant because it came on the 20th anniversary of the declaration of Kim Jong-Il as supreme commander, said professor Yang Moo-Jin at Seoul's University of North Korean Studies.

"The editorial is aimed at preparing the people for Jong-Un becoming the supreme commander of the military and also announcing it to the outside world," he told a news agency.

"Legal and official steps will follow sooner or later for his takeover from his deceased father as the supreme commander."

The latest dynastic ruler remains a figure of mystery to the outside world, which is seeking clues to future policy in the nuclear-armed nation.