North Korean leader Kim Jong Un is 'alive and well'

South Korea has said Kim Jong Un is "alive and well" following reports the leader had fallen seriously ill after undergoing heart surgery.

Moon Chung-in, the top foreign policy adviser to South Korean President Moon Jae-in, told CNN: "Our government position is firm.”

"Kim Jong Un is alive and well. He has been staying in the Wonsan area since April 13. No suspicious movements have so far been detected."

North Korean leader Kim Jong Un is 'alive and well'

The North Korean leader, 36, was last seen in public on 11 April at a meeting of the ruling Workers' Party politburo.

But four days later he was absent while the rest of the country celebrated the birthday of his late grandfather and state founder Kim Il Sung.

His lack of attendance sparked rumours about his health including Japanese magazine Shukan Gendai’s report that Kim Jong Un was in a “vegetative state” after heart surgery earlier in the month.

The third-generation hereditary leader, who came to power in 2011 following the death of his father, has no clear successor.