Amid media reports that North Korea’s top leader Kim Jong Un is in a  ‘vegetative state,’  a top security adviser to the South Korea’s President Moon Jae-in said that he is “alive and well,” downplaying rumours over Kim’s health following his absence from a key anniversary.

Earlier this week, the North Korean leader was gravely ill following heart surgery. China had dispatched a team to North Korea to advise on Kim’s health, the media report further said.

Moon’s special adviser on national security Moon Chung-in said, “Our government position is firm,” in an interview with CNN on Sunday. “Kim Jong Un is alive and well.”

“Kim had been staying in Wonsan since April 13. No suspicious movements have so far been detected.” said the adviser. Wonsan is a resort town in the country’s east.

Pyongyang marked the birthday of its late founder, Kim’s grandfather Kim Il Sung, on April 15 — by far the most important date in its annual political calendar. Kim was not seen in attendance, raising speculations about his health.

Kim has not made a public appearance since presiding over a Workers’ Party politburo meeting on April 11, and the following day state media reported him inspecting fighter jets at an air defence unit.

His absence unleashed a series of unconfirmed media reports over his condition, which officials in Seoul previously poured cold water on.

South Korea’s  presidential office said in a statement last week, “We have nothing to confirm and no special movement has been detected inside North Korea as of now.”

South Korea’s unification minister Kim Yeon-chul reiterated Monday that remained the case, adding the “confident” conclusion was drawn from “a complex process of intelligence gathering and assessment”.

Earlier this week, the North Korean leader was gravely ill following heart surgery.

Daily NK, an online media outlet run mostly by North Korean defectors, has reported Kim was undergoing treatment after a cardiovascular procedure earlier this month.

Citing an unidentified source inside the country, it said Kim, who is in his mid-30s, had needed urgent treatment due to heavy smoking, obesity and fatigue.

Soon afterwards, CNN reported that Washington was “monitoring intelligence” that Kim was in “grave danger” after undergoing surgery, quoting what it said was an anonymous US official.

On April 23, US President Trump rejected reports that North Korean leader Kim Jong-un was ailing and criticized his frequent nemesis CNN for running the story.

Trump’s denial of the report came two days after he declined to comment, saying only that he wished Kim well.

On Monday, the official Rodong Sinmun newspaper reported that Kim had sent a message of thanks to workers on the giant Wonsan Kalma coastal tourism project.

It was the latest in a series of reports in recent days of statements issued or actions taken in Kim’s name, although none has carried any pictures of him.

a US-based think tank  38North reviewed satellite images that showed a train probably belonging to Kim at a station in Wonsan last week.

It cautioned that the train’s presence did not “indicate anything about his health” but did “lend weight” to reports he was staying on the country’s eastern coast.

In North Korea it is notoriously difficult for journalists to  report, especially regarding anything to do with its leadership, which is among its most closely guarded secrets.

Earlier, in 2014 he dropped out of sight for nearly six weeks before reappearing with a cane. Days later, the South’s spy agency said he had undergone surgery to remove a cyst from his ankle.

The North Korean leader Kim Jong- Un is the Supreme leader of North Korea after he took over in 2011 when his father and late leader Kim Jong-il died.