South Korea has said that Kim Jong-un, is “alive and well”, downplaying rumours that suggested the North Korean leader was seriously ill after undergoing heart surgery. 

South Korea foreign policy adviser Chung-in Moon said that Kim was “alive and well” and his government’s position is that the leader is not dead.

READ MORE: Kim Jong Un rumours spark succession speculation 

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

And reports in North Korea have also suggested that the leader is alive and well.

The Rodong Sinmun newspaper has claimed that the North Korean leader sent a thank you message to builders on a tourism project at a seaside resort.

READ MORE: Is Kim Jong Un dead? Satellite photos locate North Korean leader's train as health rumours persist

Kim, 36, was last seen in public on 11 April but has been absent at a host of national celebrations sparking rumours of his whereabouts.

Questions about his health flared after he skipped an April 15 commemoration of the 108th birthday of his grandfather, North Korea founder Kim Il Sung.

It is thought that the leader underwent surgery however, the exact details are not yet known due to the tight controls on information in the state. 

No recent pictures of the leader have yet been seen. Satellite photos provided by website 38 North and Airbus show a train, likely to be that of the leader, parked at Mr Kim’s compound in Wonsan on his country’s east coast since at least April 21.

CNN last week reported that Kim was in "grave danger" following the surgical procedure, citing an anonymous US official. Rumours of his death have been circulating on social media.