Kim Jong-un appointed as general by North Korea

But analysts said it was still uncertain whether the younger Kim would lead the country following his father's death, and if so how independent he would be. They portrayed his current situation as effectively a probation period.

In its first ever mention of Kim Jong-un, state news agency KCNA said the 26- or 27-year-old had been given the rank of general.

"He will be the crown prince. That's it. There is no doubt," said Dr Kongdan Oh of the Brookings Institute. But she added: "The father provides a halo effect – the question is what happens when Kim Jong-il dies. That will be an interesting time."

Professor Hazel Smith, a North Korea expert at Cranfield University, said: "This does not mark a transition [of power] as such, but probably marks a step towards the son becoming more public. We have not seen the end of the process here: there is an element of probation." She added: "I don't think he will be fully trusted [by everyone in the elites] – he has spent too much time outside the country."

KCNA also reported that Kim's sister Kyong-hui, who has accompanied him frequently on public outings in recent times, was also named as a general.