Kim Jong Un looks through binoculars
'Threat to Kim Jong-un' sparks shutdown of Pyongyang, North Korea's capital cityKorean Central News Agency/Reuters

North Korean dictator Kim Jong-un may have been spirited out of Pyongyang amid reports the capital city of the Stalinist regime has gone into lockdown.

Details are scant but watchers of the Hermit Kingdom said the fact nobody is being let in or out of Pyongyang is highly significant and could point towards a coup plot.

But it is not known if it means that a coup is unfolding or is being crushed by the Kim Jong-un.

The young dictator, believed to be 31, has reigned as supreme leader for around three years and has already conducted a bloody purge to shore up his position as leader.

The fact the travel restrictions have come into force could mean control of the regime's heartland has been seized by unknown plotters, or that Kim is conducting another purge of his rivals in the hierarchy.

Two high-ranking members of the National Defence Commission have been demoted recently to much more junior positions. It is not known if this was related to the lockdown in Pyongyang.

An expert on North Korea said: "This sort of action suggests there has either been an attempted coup or that the authorities there have uncovered some sort of plot against the leadership."

Professor Toshimitsu Shigemura, of Tokyo's Waseda University, told the Telegraph: "If it is a military-backed coup, then the situation in Pyongyang will be very dangerous and I have heard reports that Kim has been moved out of the capital.

"Another reason might be that some senior officials of the regime have attempted to defect and they are closing the escape routes, such as the airport and the border."

Meanwhile, reports allege Kim's younger sister, Kim Yo-jong, is running the country in the North Korean dictator's absence due to his mysterious illness.

Kim Yo-jong
Kim Yo-jong, the younger sister of the North Korean leader, is pictured casting her vote for parliamentary elections in March 2014North Korean TV News