There are fresh signs that Kim Jong-un has stopped making decisions amid unverified claims about his health and whereabouts, a Japanese publication claims.
Proposals sent to the North Korean leader for his approval and signature have not been returned to the ruling Workers' Party of Korea state institutions at the usual pace, it is said.
Some state offices haven't received any documents with Kim's signature since mid-April, which is an unusual development, the report added.
It comes amid claims that Kim Yo-jong, 32, the dictator's younger sister, has been wielding greater power in Pyongyang and may be expanding her role as official successor.
Kim, believed to be about 36-years-old, made his last public appearance on April 11 and state media has made no mention of his health or his absence, now in its third week.
There have been widely varying reports about his status - from being dead or in a vegetative state to being "alive and well" or recovering in the countryside after heart surgery.
Claims about Kim or North Korea's activities are next to impossible to verify due to the country's secrecy and isolation.
Experts have said that it is likely only a handful of people close to the dictator know the truth.
There are new signs that Kim is not performing his usual duties or making decisions, Gendai Business reported.
The publication said it spoke to a "high-ranking" defector who claims the ruling party and state institutions have been waiting weeks to find out if proposals have been approved and signed by Kim.
The same report claims German doctors travelled to North Korea to treat Kim in mid-February after Pyongyang initially requested a team from France.
South Korea's National Assembly Research Services, a legislative think tank, has said that Kim's sister has recently been exerting increasing clout in Pyongyang, the Yonhap News Agency reported.
The think tank said Kim Yo-jong's appointment to North Korea's Politburo "will strengthen the governing foundation of the Paekdu bloodline".
It refers to the Kim dynasty and the sacred Mount Paektu, where Kim's late grandfather, the country's founder Kim Il-sung, organised the resistance against occupying Japanese forces.
North Korean propaganda claims Kim's father, Kim Jong-il was born on the mountain, although birth records from the Soviet Union say he was born in the Siberian village of Vyatskoye.
The think tank's report adds: "This suggests the possibility of expanding her status and role as official successor."
But a source in Pyongyang told Daily NK that Kim Yo-jong "essentially has no chance" of taking over given that she is not considered a "real" successor.
The country has been ruled only by Kim men since it was founded after the Second World War.
If Kim Yo-Jong gained power, it would be an "insult" to the "people", the source added.
Rumours about Kim's health and claims that he has died have been spreading through the country, the report added.
Speculation erupted after Kim missed an annual birthday celebration for his late grandfather - a major date on the calendar in North Korea - on April 15.
It was followed by a report from the Seoul-based website Daily NK, which is run by defectors, that claimed Kim had undergone heart surgery on April 12.
Kim's condition was considered stable following the operation and he was recovering at a villa while doctors continued to monitor him, a source inside North Korea told the website.
Since that report, there have been unverified claims that Kim is dead, in a vegetative state or "alive and well".
South Korea's presidency has said no unusual movements have been detected in North Korea and cautioned against reports that Kim may be ill.
Defense Minister Jeong Kyeong-doo said on Wednesday that Kim taking an extended absence from public view is nothing new.
He told lawmakers: "Our intelligence shows that there are no abnormalities, no unusual movements in North Korea."
There is speculation that Kim has travelled to his seaside compound in Wonsan after a train, believed to be his, was spotted at a station there in satellite images published by the Washington-based North Korea monitoring project, 38 North.
It has been claimed he left Pyongyang for his coastal retreat due to a coronavirus outbreak in the country.
New satellite images published by NK Pro show recent movements of luxury boats often used by Kim off the coast of Wonsan.
It is where the dictator keeps a Princess 95 luxury yacht that was once valued at $7 million.
