UPDATE: Power restored on Danish island Bornholm

Energy companies Trefor El-net Øst and Bornholms Energi og Forsyning (Beof) both confirmed the outage, news wire Ritzau reported on Monday morning.

“The whole island is without electricity,” Trefor’s head of media relations Anya Palm told Ritzau.

“We were informed of a disruption at 7:49am. We are continuously monitoring the entire electricity network and can see there’s a break in supply. But we can’t see why,” she said.

The underwater cable used to supply electricity to Bornholm is owned by state infrastructure company Energinet.

“The cable has stopped working and we are in the process of finding the problem. We are working hard to find out the cause,” Energinet saidu early on Monday

Trefor said its first priority was to reinstate the electricity supply before investigating the cause of the outage.

“We are aware that there has been activity around Bornholm in recent weeks, so it is important to say that we don’t yet know what has happened. But there is no cause for speculation, it is likely to be a normal power break,” Palm said.

Electricity was cut to the island's 40,000 residents at 7:50am  but was restored four hours later, Energinet said.

Initially concerned the problem could be linked to an underwater cable linking the island to the continent, Energinet concluded that a "local problem" on Bornholm was at fault.

"It's a local breakdown on the island," an Energinet spokeswoman said.

The incident occurred two weeks after the discovery of four major gas leaks just off Bornholm on the two Nord Stream gas pipelines linking Russia to Germany, which investigators have attributed to underwater detonations probably due to sabotage.

Russia, the focus of the West's suspicions, has rejected any responsibility and has in turn accused the West.

Denmark has heightened security around its energy infrastructure since the gas leaks were discovered.

Last week, Danish police said they had also received reports of unauthorised drone flights near North Sea gas fields, following similar incidents in Norway.