North Korean state TV footage on Sunday showed Jang Song-thaek, the power behind the communist state's throne, wearing a military uniform with the insignia of a general, another sign of his rising influence after the death of Kim Jong-il.
The footage, which state TV said was taken on Saturday, showed Jang at the front of rows of top military officers who accompanied Kim Jong-un, the youngest son of Kim Jong-il and his anointed successor, paying their respects in front of Kim's body.
North Korea announced on Monday Kim Jong-il had died of a heart attack on December 17. His body is lying in state in a mausoleum in Pyongyang. He was believed to be 69.
His death sparked fears about succession in the reclusive communist state, which has been ruled by Kim's family since shortly after World War Two.
It also unnerved neighbours Japan and South Korea, as well as Seoul's key ally, the United States, as they wait to see how the succession plays out in the unpredictable hermit state.
Kim Jong-un was hailed by state media on Saturday as supreme commander of the North's 1.1 million-strong armed forces, the title held by his father.
While the younger Kim has been described as the Great Successor, a senior source told Reuters this week Pyongyang will shift from a strongman dictatorship to a coterie of rulers including the military and Jang, Kim Jong-un's uncle.
Kim Jong-un, in his late 20s, has also been called by his official title of vice-chairman of the Central Military Commission of the North's ruling party.
Jang married the daughter of the country's autocratic founder, Kim Il-sung, in 1972, to join the ruling family.
A Seoul official familiar with North Korea affairs said it was the first time Jang has been shown on state TV wearing a military uniform. His appearance was interpreted as meaning he has secured a key role in the North's powerful military, which has pledged its allegiance to Kim Jong-un.
POWER BEHIND THE THRONE
Sources with close ties to North Korea and China have said Jang is the real power behind Pyongyang's succession process.
North Korea's state media have geared up their propaganda machine since Saturday in an apparent bid to smooth the untested Kim Jong-un's succession and show his grip on the military, which is trying to develop a nuclear arsenal.
The Japanese government will hold consultations with the governments of prefectures along the coast of the Sea of Japan to seek their support in accommodating North Koreans in case of a possible flood of refugees, Kyodo News said on Saturday.
Japan has already picked several public facilities in prefectures such as Niigata, Ishikawa and Fukuoka to serve as temporary shelters for North Korean refugees, Kyodo said, but the government needs to expand the list.
Experts say Tokyo has made contingency plans for possibly tens of thousands of refugees arriving at its ports but has not obtained local agreement to the plans, a potential headache.
Prime Minister Yoshihiko Noda instructed government officials on Monday to make preparations for all possible contingencies. Noda is due to arrive in Beijing later on Sunday for talks with Chinese leaders, with North Korea expected to be high on the agenda.
China has been the North's major backer during decades of isolation and Noda will meet President Hu Jintao and Premier Wen Jiabao during a two-day trip. They are expected to agree to work together TO maintain stability on the Korean peninsula.
The two Koreas are still technically at war after the 1950-53 Korean War ended with a ceasefire rather than an armistice.
(Additional reporting by Mari Saito in TOKYO; Editing by Paul Tait)