The South Korean government on Tuesday said it had detected no unusual developments in North Korea after media reports claimed that the country’s leader, Kim Jong-un, was “in grave danger” following a surgery, reported AP. Speculation about Kim’s health started doing the rounds after he missed the celebration of his late grandfather and state founder Kim Il Sung’s birth anniversary on April 15.

“We have no information to confirm regarding rumours about Chairman Kim Jong-un’s health issue that have been reported by some media outlets,” Seoul’s presidential spokesperson Kang Min-seok said in the statement. “Also, no unusual developments have been detected inside North Korea.”

South Korean news website Daily NK was the first to report that the North Korean leader was recovering from a heart surgery in Pyongyang. The report, which cited anonymous officials, said Kim’s condition was improving. Later, CNN cited an anonymous US official who said Kim was in grave danger after an unspecified surgery. Another US official told the news network that the concerns about Kim’s health were credible but its severity was yet to be ascertained.

Getting inputs from North Korea has always been very difficult as the nuclear-armed country tightly controls any information surrounding its leader. “There have been a number of recent rumours about Kim’s health [smoking, heart, and brain],” Bruce Klingner, a senior research fellow at the Heritage Foundation and former CIA deputy division chief for North Korea, told CNN. “If Kim is hospitalised, it would explain why he wasn’t present on the important April 15 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.”

Kim’s absence from state media had triggered speculations about his health earlier also. In 2014, he was not in the public eye for nearly six weeks. Days later, South Korea’s spy agency said he had a cyst removed from his ankle.