Meanwhile, Kim Yong Nam, North Korea's No. 2 in command, said there was "no problem" with the ruler's health and rumors to the contrary weren't true, The Guardian reported Wednesday.
However, Won Hye-young, a leader in South Korea's main opposition Democratic Party, said, "Kim suffered either a stroke or a cerebral hemorrhage but is recovering, the intelligence agency said. Pyongyang is not in a state of administrative vacuum," Yonhap News Agency reported.
"Although Kim is not fit enough for outside activity, he is conscious and able to control affairs," Won said.
North Korean officials took the unusual step of granting interviews with foreign news agencies, seeking to end speculation regarding Kim's health. He was absent from Tuesday's celebrations marking the 60th anniversary of the country's founding.
Observers said Kim, 67, has been known to disappear from public view for months but added that it was unusual for Kim to miss a major event, such as Tuesday's anniversary, the British newspaper said.
Kim's condition is of concern internationally because there is no clear line of succession and the country recently resumed its nuclear program. Officials said the United States' failure to remove North Korea from its list of states that sponsor terrorism led to the program's resumption.