South Korean officials reported no unusual activity in North Korea on Tuesday following unconfirmed media reports that leader Kim Jong Un was in fragile health after surgery.

"I just hope he's doing fine", Trump told a White House news conference on Tuesday. "I don't necessarily think that either the USA or South Korea has any way to know", said Barry. And I'd like to see him do well. Kim Joon-hyung, head of the Korea National Diplomatic Academy, said on a radio program Wednesday that it was impossible for information on Kim Jong-un's health to leak out in such a secretive country within days of his supposed sickness.

One such possible indicator is an April 15th celebration for the birthday of KJU's grandfather, Kim Il-sung.

In North Korea, Kim Jong-un is the single face and leader of the regime.

The official Rodong Sinmun newspaper published older or undated comments attributed to Kim about the economy, the textile industry and city development, among other topics.

There was no mention of Kim's whereabouts.

Kim Jong-un underwent the procedure at a hospital in the county of Hyangsan on the country's east coast on 12 April, according to the Daily NK, which is run mostly by North Korean defectors.

"My understanding is that he had been struggling (with cardiovascular problems) since last August but it worsened after repeated visits to Mount Paektu", a source was quoted as saying, referring to the country's sacred mountain. On Tuesday, reports citing anonymous sources claimed Kim was gravely ill following surgery.

A CNN report then cited an unnamed USA official saying the United States was "monitoring intelligence" that Kim was in grave danger after surgery.

Since then, two South Korean government officials rejected the CNN report.

Some experts say his sister and close associate Kim Yo Jong is most likely since North Korea has been ruled by the Kim family for seven decades. "Kim is also believed to have been at a location in Munchon, near Wonsan, where the North Korean military launched a cruise missile on April 14".

"Since April 11 to now, [Kim Jong-un] has not been seen in the public eye, but there have been testimonials that he was present at various undisclosed ceremonies in the provinces until the last weekend", Kim Joon-hyung said.

State media since reported he sent greetings to Syrian President Bashar al Assad and Cuban President Miguel Díaz-Canel as well as arranging special birthday meals for two North Korean officials and a new centenarian. He failed to attend a series of public events over a period of six weeks from October 2014 and was using a walking stick when he eventually reappeared.

Yoon said that this move was obviously to prepare a successor.

Outside governments and media have a mixed record on tracking developments among North Korea's ruling elite, made hard by the North's stringent control of information about them.

Yun said for all its secrecy, North Korea in recent years had been quick to respond to significant foreign news reports and it is noteworthy that it has stayed silent so far.

"The basic assumption would be maybe it would be someone in the family", U.S. National Security Adviser Robert O'Brien said, when asked what the succession would look like, according to footage aired by CNN. Some analysis suggests KJU's sister, Kim Yo-jong, as a possible candidate to assume power following her ascendancy in the Communist Workers' party as the nation's - and KJU's - chief propagandist.

She accompanied Kim Jong Un on his high-stakes summits with U.S. President Donald Trump and different world leaders in recent times.

He is believed to be disinterested in public life and is unlikely to emerge as a major presence, though some analysts say he maintains ties with siblings and could play a more public role in a contingency.