A South Korean official on Tuesday played down a CNN report that North Korean leader Kim Jong-un was in critical condition after surgery.

Citing a US official with direct knowledge of the matter, the US news channel said Kim appeared to be in "grave danger" after surgery.

An earlier report by a South Korean online media outlet specializing in North Korea news said that Kim had undergone heart surgery and was in recovery.

Kim was not present at the celebration of the birthday of his grandfather Kim Il-sung on April 15, fueling speculation about his health. It was the first time he had been absent from the event since he came to power in 2012.

In response to the CNN report, a Seoul official told Yonhap News Agency that nothing particular pointed to Kim's failing health, saying Kim had made several public appearances until recently. Kim last appeared on April 11, when the North's ruling party held a politburo meeting.

Seoul's Unification Ministry, which handles inter-Korean affairs, said it had no comment.