A fire at a key electricity link in southwest Berlin cut power to tens of thousands of households and businesses, prompting authorities to describe the incident as a suspected far-left extremist attack.
The blaze, which broke out early on Saturday, damaged high-voltage cables and triggered one of the city’s most disruptive outages in recent years.
Grid operator Stromnetz Berlin said the disruption could leave some residents without electricity and heating until January 8, depending on repair conditions.
Berlin’s interior affairs minister, Iris Spranger, said security authorities had classified as authentic a letter claiming responsibility for the attack.
The message was attributed to a far-left group known as the Volcano Group, which said it targeted energy infrastructure linked to fossil fuels.
Spranger condemned the incident as an inhumane act and said investigations were continuing.
Berlin Mayor Kai Wegner said the blackout appeared politically motivated and warned that such actions endangered lives.
State security officials said the incident bore similarities to previous attacks attributed to far-left militants.
Stromnetz Berlin initially reported that up to 45,000 households and more than 2,000 businesses were affected in districts including Zehlendorf, Wannsee, and Lichterfelde.
By Sunday, electricity had been restored to around 10,000 households, though thousands remained without power.
Cold weather and snowfall slowed repair work, particularly efforts to install new underground cables.
The outage disrupted commuter rail services, mobile networks, and daily life, with police using loudspeakers to relay information.
Elderly care homes, hospitals, and residents dependent on elevators were among those affected.
Authorities said earlier theories of foreign sabotage were ruled out as evidence pointed to domestic extremist involvement.
The Volcano Group has previously claimed responsibility for attacks on energy infrastructure, including an incident near a Tesla facility in 2024.