By Benjamin Kang Lim and Tony Munroe
BEIJING/SEOUL, Oct 9 (Reuters) - North Korean leader Kim Jong Un is in firm control of his government but has hurt his leg, a source with access to the secretive North's leadership said on Thursday, playing down speculation over the 31-year-old's health and grip on power.
North Korea's state media, which usually chronicles Kim's whereabouts in great detail, has not made any mention of his activities since he attended a concert with his wife on Sept. 3.
The source said that Kim hurt his leg while inspecting military exercises.
"He ordered all the generals to take part in drills and he took part too. They were crawling and running and rolling around, and he pulled a tendon," the source told Reuters on condition of anonymity.
"He injured his ankle and knee around late August or early September while drilling because he is overweight. He limped around in the beginning but the injury worsened," the source said.
Kim, who has rapidly gained weight since coming to power after his father died of a heart attack in 2011, had been seen walking with a limp since an event with key officials in July, which would imply he may have aggravated an earlier injury.
Kim needs about 100 days to recuperate, said the source, whose information could not be independently verified.
"Kim Jong Un is in total control," said the source, who has close ties to Pyongyang and Beijing.
Friday is the 69th anniversary of the founding of North Korea's Workers' Party, an event Kim has marked in the past two years with a post-midnight visit to the Pyongyang mausoleum where the bodies of his father and grandfather are interred.
If Kim does not turn up, it could fuel speculation over the state of his health and whether he may have been sidelined in a power struggle, experts said.
"The longer he remains out of the public eye, the more uncertainty about him, and the status of his regime, will grow," said Curtis Melvin, a researcher at the U.S.-Korea Institute at the Johns Hopkins School of Advanced International Studies in Washington.
NOT KIM'S FIRST ABSENCE
North Korean officials have denied that Kim's public absence since early September is health-related and a U.S. official following North Korea said this week there were no indications he was seriously ill or in political trouble.
It remains unclear why a leg injury would keep Kim out of the public eye for so long, although this is not the first time he has been missing from public view.
In June 2012, six months after coming to power, state media failed to report on or photograph him for 23 days.
He re-surfaced the next month at a dolphinarium.
Speculation that Kim's unusually long absence from public view may be due to ill health was fueled by a North Korean TV report late last month that said he was suffering from "discomfort."
Some Pyongyang watchers also suggest that Kim may have been sidelined in a power struggle, a scenario they say was reinforced by the unexpected visit on Saturday of a high-level delegation to the closing ceremony of the Asian Games in Incheon, South Korea.
Another interpretation of that visit holds that it was meant to convey stability in Pyongyang.
The source with knowledge of Kim Jong Un's health said rumors of a coup were "rubbish."
"It would have to be a very subtle coup indeed not to disrupt international travel plans," said Andray Abrahamian of the Choson Exchange, a Singapore-based NGO running a program for North Koreans in Southeast Asia.
North Korea is a hereditary dictatorship centered on the ruling Kim family. Kim's sister, Kim Yo Jong, is known to have an official role within the ruling party. His brother, Kim Jong Chol, and his estranged half-brother are not in the public eye.
Kim was absent from a Sept. 25 meeting of the Supreme People's Assembly, or parliament, the first he has not attended since coming to power three years ago.
However, Kim's name has not disappeared from state propaganda.
Thursday's edition of the Workers' Party newspaper, the Rodong Sinmun, carried three letters to Kim from overseas allies on its front page, and has reported on returning athletes from the Asian Games who thanked "the Marshal" for his support during the competition.
Abrahamian said it was unlikely Kim had been usurped.
"Kim Jong Un has always shared power with other key figures and even if the internal balance of power has shifted, it is unlikely that they would want to remove him, given his unmatchable symbolic value. Again, though, everyone is guessing," he said. (Additional reporting by James Pearson; Editing by Mike Collett-White and Raju Gopalakrishnan)