The South's permanently primed North Korea rumour mill has been feeding off Kim's extended absence, and stepped up a gear when he failed to attend a session of parliament yesterday.
State television coverage of Kim in July had shown the young leader walking with a pronounced limp, and speculation over the reason for his latest no-show has ranged from an attack of gout to an injury he may have picked up while providing "guidance" to North Korean athletes competing in the ongoing Asian Games.
"North Korea has not made any official announcement... So we don't have anything to comment on", a ministry spokeswoman said.
"We are watching with various possibilities in mind, including the rumours about health problems," she added.
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The North's Supreme People's Assembly, or parliament, only meets once or twice a year to rubber-stamp budgets or other decisions made by the ruling party.
It has little real power and there is no onus on Kim to attend when it is convened, although today's session was the first he has missed since coming to power three year ago.
It is by no means unprecedented for a North Korean leader to drop out of the public eye for a while, but it is more noticeable with Kim who has maintained a particularly pervasive media presence since assuming power on the death of his father Kim Jong-Il in 2011.
Much has been made of the state TV footage that showed him limping at a national memorial meeting in July to mark the 20th anniversary of the death of his grandfather and North Korea's founder Kim Il-Sung.
Another source told the agency that a North Korean medical team had visited Germany and Switzerland for consultations on Kim's health issues.
Hong Hyun-Ik, a senior researcher at the Sejong Institute think-tank in Seoul, warned against reading too much into Kim's absence.