Lights on at North Korea's 105-storey hotel after rumoured visit by Egyptian CEO

Orascom head Naguib Sawiris is thought to have visited the Ryugyong, which his company helped to build

The lights are on at North Korea's Ryugyong Hotel, the world's tallest unoccupied building.

Three rooms at the very top of the so-called 'hotel of doom', which is still not open and has seen a number of halts in construction over 29 years, were seen to be lit up in a grainy video.

An anonymous source told NK News it might have been due to a visit to Pyongyang by Naguib Sawiris, the chief executive of Orascom. The Egyptian telecommunications company previously carried out work on the building that included adding glass panels to the outside and a phone mast.

Peter Ward, a researcher based in South Korea, also told the site after the release of the October video: "I’m very surprised to see the top of the Ryugyong lit.

"Maybe Orascom did more than give the building a fresh plate of glass.

"The fact they have added an aircraft warning light is interesting, if slightly puzzling."

Work began on the imposing structure in 1987, but construction was stalled for 16 years after the money for the project ran out.

The 330m tower has a total of 3.9 million ft² floor space and should have initially opened in 1989.

At that time it would have been the tallest hotel in the world and the seventh largest skyscraper. Reports claim the building could have up to 3,000 rooms.