Updated 11:12 PM ET
PYONGYANG, North Korea - North Korea on Sunday aired footage showing the uncle and key patron of anointed heir Kim Jong Un wearing a military uniform with a general's insignia - a strong sign he'll play a crucial role in helping the young man take over power and uphold the "military-first" policy initiated by his late father, Kim Jong Il.
The footage on state television shows Jang Song Thaek in uniform as he pays respects at Kim Jong Il's body lying in state at Kumsusan Memorial Palace. Seoul's Unification Ministry says it's the first time Jang, usually seen in business suits, has been shown wearing a military uniform on state TV.
Little by little, North Korea is offering hints on Kim Jong Un's rise and the future composition of his inner circle as millions continue to mourn for his father. North Korea has also begun hailing Kim Jong Un as "supreme leader" of the 1.2-million strong military as it ramps up its campaign to install him as ruler.
The new title and public show of support from the military leadership sent a strong signal that the nation will maintain Kim Jong Il's "military first" policy for the time being.
Earlier Saturday, the newspaper Rodong Sinmun, mouthpiece of the ruling Workers' Party, also recognized the young man's authority over the military by calling him "supreme commander" of the armed forces.
Kim Jong Un, who is in his late 20s and was unveiled in September 2010 as his father's choice as successor, will be the third-generation Kim to rule the nation of 24 million. His father and grandfather led the country under different titles, and it remains unclear which other titles will be bestowed on the grandson.
Kim Il Sung, who founded North Korea in 1948, retains the title of "eternal president" even after his death in 1994.
Son Kim Jong Il ruled as chairman of the National Defense Commission, supreme commander of the Korean People's Army and general secretary of the Workers' Party.
Kim Jong Un was promoted to four-star general and appointed a vice chairman of the Central Military Commission of the Workers' Party. He had been expected to assume a number of other key posts while being groomed to succeed his father.
His father's death comes at a sensitive time for North Korea, which was in the middle of negotiations with the U.S. on restarting talks to dismantle the North's nuclear weapons program in exchange for aid, and had been preparing for 2012 celebrations marking Kim Il Sung's 100th birthday. Suffering from a shortfall in basic staples after several harsh seasons, officials also had been asking for help feeding its people.
North Korea has emphasized the Kim family legacy during the sped-up succession movement for Kim Jong Un. State media invoked Kim Il Sung in declaring the people's support for the next leader, comparing the occasion to Kim Jong Il's ascension to "supreme commander" exactly 20 years ago Saturday.
At the Kumsusan Memorial Palace, Kim Jong Un and senior commanders paid silent tribute to the late leader, "praying for his immortality," KCNA said. The military also pledged its loyalty to Kim Jong Un, the report said.
"Let the whole army remain true to the leadership of Kim Jong Un over the army," KCNA reported a pledge reminiscent of those made when Kim Jong Il was named supreme commander.
The call to rally behind Kim Jong Un, dubbed the "Great Successor" in the wake of his father's death on Dec. 17 from a heart attack, comes amid displays of grief across North Korea. The country is to remain in an official state of mourning until after Kim's funeral Wednesday and a memorial Thursday.
In Pyongyang, mourners continued Saturday to bow and lay flowers at Kim's portrait at plazas and government buildings, including the Pyongyang Circus Theater and Kim Il Sung Square, even as temperatures dropped to 14 degrees below Celsius (7 degrees Fahrenheit).
At the April 25 People's Army House of Culture, workers at beverage kiosks handed steaming cups of water to shivering mourners, including children bundled up in colorful thick parkas. A sign urged mourners to thaw out inside a heated bus.
The order to provide food and warming huts for mourners came from Kim Jong Un, officials said.