US President Donald Trump on Saturday (local time) said he is glad to see that North Korean leader Kim Jong-Un is "back and well".

"I, for one, am glad to see he is back, and well!" Trump wrote on Twitter. He also retweeted North Korean state media photos of Kim attending a ribbon-cutting ceremony at the Sunchon Phosphatic Fertilizer Factory.

Earlier, Yonhap news agency reported that the state media on Saturday showed the North Korean leader, who was last seen on April 11, made his first public appearance after 20 days.

State media reported Kim attended a ceremony marking the completion of a fertilizer plant in Sunchon.

South Korean officials had repeatedly disputed reports of his poor health saying they have detected no unusual signs from North Korea.

The report of Kim's illness started doing rounds following his absence at the Kumsusan Palace of the Sun in Pyongyang on the birthday of late state founder and his grandfather, Kim Il-sung, last month.