Donald Trump added to the confusion about the health of North Korean leader Kim Jong-un by claiming he has a “very good idea” about the dictator’s condition.

Mr Kim’s whereabouts and health status have been a subject of intense speculation after Seoul-based website Daily NK reported last week he was recovering after undergoing a cardiovascular procedure on 12 April.

“I can’t tell you exactly,” the US president said when asked about Kim’s condition at a White House news conference on Monday. “Yes, I do have a very good idea, but I can’t talk about it now. I just wish him well.”

Suggesting the mystery would soon be cleared up, Mr Trump added: “I hope he’s fine. I do know how he’s doing relatively speaking. We will see – you’ll probably be hearing in the not too distant future.”

Yet the president appeared to contradict himself only moments later when he said “nobody knows where he is”.

Kim Jong-un: Power in pictures Show all 20 1 /20 Kim Jong-un: Power in pictures Kim Jong-un: Power in pictures Kim Jong-un rides a horse during snowfall in Mount Paektu in this image released by North Korea's Korean Central News Agency on 16 October 2019 Reuters Kim Jong-un: Power in pictures Kim Jong-un visits the newly built Pyongyang Orphans' Primary School on 2 February 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects a women's company under Unit 5492 of the Korean People's Army in November 2019 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects the test-fire of intercontinental ballistic missile Hwasong-14 at an undisclosed location in July 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un celebrates the successful test-fire of the intercontinental ballistic missile Hwasong-14 at an undisclosed location in July 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects a potato at the Samjiyon Potato Factory in North Korea in October 2018 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un rides a horse through a forest in this image released by North Korea's Korean Central News Agency on 16 October 2019 EPA Kim Jong-un: Power in pictures Kim Jong-un inspects a block of frozen fish at a processing facility in North Korea in November 2018 Reuters Kim Jong-un: Power in pictures Kim Jong-un celebrates the succeful launch of a strategic submarine-launched ballistic missile in August 2016 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un shakes hands with Donald Trump as they meet for the first time at the Capella Hotel on Sentosa island in Singapore in June 2018 Reuters Kim Jong-un: Power in pictures Kim Jong-un and Donald Trump share a glance as they meet in the Demilitarised Zone in Panmunjon, Korea in June 2019 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects mushrooms at Pyongyang Mushroom Farm AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects a super-large multiple rocket launcher ahead of a test in September 2019 Reuters Kim Jong-un: Power in pictures Kim Jong-un inspects an apple farm in South Hwanghae Province in September 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects an apple farm in South Hwanghae Province in September 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects dental wares at a newly built factory in June 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un visits Farm No 1116 in September 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un visits a motor factory in November 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un rides a horse during snowfall in Mount Paektu in this image released by North Korea's Korean Central News Agency on 16 October 2019 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects the Command of the Strategic Force of the Korean People's Army at an undisclosed location in August 2017 AFP/Getty

It comes as the North Korea authorities publishing a letter purportedly from Mr Kim to South African president Cyril Ramaphosa – dated 27 April – as “proof” that he is alive and well.

State media have previously reported that he sent greetings to Syrian president Bashar Assad and Cuban president Miguel Diaz-Canel.

Not seen in public since 11 April, the leader’s absence from public ceremonies on the birth anniversary of his grandfather Kim Il Sung on 15 April was unprecedented – leading to days of speculation over his health.

South Korean officials have cautioned against reports that Kim may be ill and emphasised they have detected no unusual movements in North Korea.

Donald Trump speaking at a news conference on 27 April, 2020 (AFP via Getty Images) (AFP/Getty)

South Korea’s minister for North Korean affairs said on Tuesday that Mr Kim may have missed the key holiday because of concerns over the coronavirus, not because he is ill.

“It is true that he had never missed the anniversary for Kim Il Sung’s birthday since he took power, but many anniversary events including celebrations and a banquet had been cancelled because of coronavirus concerns,” Kim Yeon-chul said at a parliamentary hearing.

He said there were at least two instances since mid-January where Kim Jong Un was out of sight for nearly 20 days. “I don’t think that’s particularly unusual given the current [coronavirus] situation.”

A special train possibly belonging to Mr Kim was spotted last week at the North Korean resort town of Wonsan, according to satellite images reviewed by 38 North, a Washington-based North Korea monitoring project.

Despite Mr Trump’s claim to have a “very good idea” about his condition, experts said nobody outside North Korea knew exactly what was happening.

Cheon Seong Whun, a presidential secretary during the South Korea’s previous conservative government, said Seoul had struggled for several decades to get a strong grip on the location and health of North Korea’s top leadership.

“Anybody who says they know something for certain is just writing a novel,” Mr Cheon said.