North Korean leader Kim Jong-un is reportedly in a coma and his sister Kim Yo-jong will be exercising de facto control over national and international matters, several media outlets said quoting a former aide of South Korea’s late president Kim Dae-jung.

Chang Song-min, who served Kim Dae-jung as a political affairs secretary and as head of the state affairs monitoring office, reportedly claimed in a social media post that no North Korean leader would entrust any of his authority to another person unless he was too sick to rule or was removed through a coup.

“I assess him (Kim Jong Un) to be in a coma, but his life has not ended,” he was quoted as saying by The Korea Herald. “A complete succession structure has not been formed, so Kim Yo-jong is being brought to the fore as the vacuum cannot be maintained for a prolonged period,” he added.

Chang claims to have secured the information from a source in China that Kim is “comatose.”

According to the South Korean daily, Seoul’s spy agency told lawmakers in a closed-door meeting about a ruling system that Kim seemed to have set up following which he shall share authority and responsibility with his most trusted aides. The National Intelligence Agency, however, said that the new system is not associated with any serious health issue.

Chang’s claims come months after the North Korean dictator had not made a public appearance amid speculations of his deteriorating health. He was last seen presiding over a Workers’ Party politburo meeting on April 11 before a top security adviser to the South’s President Moon Jae-in downplayed rumours and said Kim Jong Un was “alive and well”.

He was then seen cutting the ribbon at the opening of a fertilizer factory on May 2, KCNA reported.

However, Chang has claimed that all photographs of Kim released by North Korea in recent months were fake.