A group of left-wing extremists has claimed responsibility for the suspected arson attack that shut down the Tesla Gigafactory outside of Berlin on Tuesday.

The group, which calls itself “Vulkangruppe Tesla Abschalten” (also known as “Vulcan Group” or “Volcano Group”), said in a statement posted to Kontrapolis.info that it aimed to cause “the largest possible blackout of the Gigafactory,” citing environmental and labor concerns as motivations behind the attack. (Google Translate was used to translate the letter from German to English. All quotes in this article are from that translation.)

Production was halted at the factory after the attack on a nearby electricity pylon cut power to the facility. Reuters reports that production isn’t expected to resume until “at least early next week,” with the outage reportedly costing Tesla estimated losses in the “high hundred of millions of euros.” On X, Tesla CEO Elon Musk condemned the attack, referring to Volcano Group as “the dumbest eco-terrorists on Earth.”

“We sabotaged Tesla today,” the group said, claiming the factory “eats up earth, resources, people, labor and spits out 6,000 SUVs, killing machines and monster trucks per week.” The 2,500-word letter goes on to accuse the Gigafactory of contaminating groundwater and requiring large quantities of drinking water to produce electric vehicles, echoing similar concerns raised by officials from the local water authority near the facility in February.

Plans to extend the German Tesla factory, which was opened in Grünheide in 2022, have faced major hurdles after locals voted against the expansion in a nonbinding survey in February this year. Opponents argued the expansion project could impact water protection zones in the area. The Brandenburg region, where Grünheide is located, has been impacted by drought conditions for several years. Climate activists have also occupied the forest around the Gigafactory to protest its impact on the local water supply.

According to Reuters, German police believe the Volcano Group letter, which was signed “Agua De Pau,” the name of a volcanic mountain in the Azores, is authentic. A 2019 report (pdf) published by German authorities says that various crimes have been committed under the Vulkangruppe moniker following a surge in arson attacks on cars in 2011, with perpetrators often using the names of Icelandic volcanoes as an alias. The group has also previously claimed responsibility for another arson attack in Grünheide in 2021 during the construction of the Tesla Gigafactory.