The South Korean government on Tuesday said it was looking into US media reports that North Korean leader Kim Jong Un was in a fragile condition after surgery.
Officials from South Korea’s Unification Ministry and National Intelligence Service said they could not immediately confirm the report.
CNN cited an anonymous US official who said Mr Kim was in “grave danger” after an unspecified surgery.
The Unification Ministry, which deals with inter-Korean affairs, said it could not confirm another report by Daily NK, which cited anonymous sources to report Mr Kim was recovering from heart surgery in the capital Pyongyang and that his condition was improving.
Speculation about Mr Kim’s health was raised after he missed a celebration honouring his late grandfather and state founder Kim Il Sung on April 15.
He had been seen four days before that at a government meeting.
South Korea’s presidential office said in a statement no suspicious activity had been detected in North Korea that may have given backing to the reports.
The absence of Mr Kim’s father and predecessor as the country’s leaders, Kim Jong Il, absence from a parade celebrating North Korea’s 60th anniversary in 2008 was followed by rumours that he was in poor health.
It was later revealed he had a stroke, after which his health declined further until his death in 2011.
Credible information about North Korea and especially its leadership is difficult to obtain and even intelligence agencies have been wrong about its inner workings in the past.
CNN quoted Bruce Klingner, a senior research fellow at the Heritage Foundation and former CIA deputy division chief for North Korea, as saying rumours had circulated recently about Mr Kim’s health.
“There have been a number of recent rumours about Kim’s health (smoking, heart, and brain),” the network quoted Mr Klingner as saying.
“If Kim is hospitalised, it would explain why he wasn’t present on the important April 15th celebrations.
“But, over the years, there have been a number of false health rumours about Kim Jong-un, or his father. We’ll have to wait and see.”