Pyongyang is reportedly under lockdown, raising fears of a possible coup to overthrow leader Kim Jong Un or his top leadership, experts told the Telegraph. Attempted defections of North Korean leaders may have also prompted the lockdown, which includes travel restrictions in the North Korean capital.

"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," North Korean expert Toshimitsu Shigemura, a professor at Waseda University in Tokyo, told the Telegraph in a story published Friday. "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.”

Reports of the lockdown first surfaced in a story Tuesday in New Focus International. North Korea's leader has not been seen publicly for more than a month. His little-known sister, Kim Yo Jong, is reportedly in charge of North Korea as he undergoes medical treatment. The New Focus International piece said it could not say whether his alleged health troubles were the reason for the lockdown.

Shigemura said defections of North Korean leaders may have also cause the reported lockdown. "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," he said.

Other possibilities include a purging of North Korean leaders, according to the Telegraph. Jang Song Thaek, Kim’s uncle, was executed last December after being branded a traitor. A Hong Kong-based, pro-Chinese newspaper claimed he was eaten alive by 120 dogs.