A broadcast by North Korean media has shown a portrait of North Korean leader Kim Jong Un being displayed alongside those of his predecessors for the first time. An expert says this is a sign of Kim's confidence in his own rule, which has lasted for more than 10 years.

The North's state-run Korean Central Television reported on Wednesday that Kim attended a ceremony to mark the completion of a party cadre training school in the capital Pyongyang on the previous day.

The broadcast showed Kim's portrait displayed alongside those of his grandfather, Kim Il Sung, and his father, Kim Jong Il, in a classroom.

Radio Press, which monitors North Korean media, says it is the first time that such a display has been confirmed in official media coverage.

In a speech, Kim said, "Anyone who visits here can find a clear answer to how the lifeline of the party and the revolution is given continuity."

Keio University Professor Isozaki Atsuhito, an expert on North Korea, said the display reflects the current leader's confidence in his rule, which has lasted more than 10 years, and places him on the same level as his predecessors. He said it also shows that now is the era of Kim Jong Un.

He added that as Kim's daughter's existence becomes known, the display of hereditary succession of power could serve as a message of the regime's continuity. He suggested that the move might hint at the potential for a fourth-generation succession.