TOKYO (Yonhap News) -- The eldest brother of North Korea’s new leader Kim Jong-un has expressed doubts about his half-sibling’s hold on power, anticipating the ruling elite to extend their influence over the communist country, a Japanese newspaper said Thursday.

Kim Jong-nam told the Tokyo Shimbun in an e-mail sent on Jan. 3 that he has “doubts about how a young successor with some two years (of training as heir) can retain the 37 years of absolute power”wielded by his late father and former leader Kim Jong-il, the newspaper said.

Kim Jong-nam, believed to be in his late 30s, has lived abroad for years after apparently falling out of favor with his father for attempting to enter Japan on a fake passport in 2001.

A source familiar with Kim’s activity told Yonhap News Agency last month that the eldest son had arrived in Beijing from the Chinese gambling enclave of Macau, shortly before Pyongyang held a state funeral for his father on Dec. 28. It remains unclear whether Kim Jong-nam attended the funeral.

“I expect the existing ruling elite to follow in the footsteps of my father while keeping the young successor as a symbolic figure,” he said in the e-mail, making his first remarks on the North Korean regime and succession process since his father’s death.

“It is difficult to accept a third-generation succession under a normal reasoning (process).”

It is not the first time Kim Jong-nam has been critical of the hereditary succession in his country that started when his father inherited power from his own father and North Korea founder Kim Il-sung in 1994.

Kim Jong-nam told the Tokyo Shimbun in January last year that “even Chairman Mao Zedong of China did not enforce hereditary succession.”

“(Hereditary succession) does not fit with socialism, and my father was against it as well,” he was quoted as telling the paper in an exclusive interview held in a southern Chinese city.