A far-left activist group has claimed responsibility for a suspected arson attack which saw Tesla halt production at its Berlin car factory on Tuesday.
In a letter published online, activists calling themselves the Volcano Group say they sabotaged production.
An electricity pylon close to the plant caught fire, causing power outages in the factory and nearby towns.
Tesla said workers had been sent home but its building was in a "safe state".
The fire did not reach the electric car-maker’s factory itself but did burn an electricity pylon and high-voltage wires.
In its letter claiming responsibility for the attack, the Volcano Group said it sabotaged Tesla because it ate up resources and labour.
It also accused Tesla of contaminating groundwater and using huge amounts of drinking water.
The BBC has contacted the car firm for its response to the accusations.
The Reuters news agency has reported that state police are checking the authenticity of the letter.
"The rule of law will react to such an act of sabotage with the utmost severity," said Interior Minister for Brandenburg state Michael Stuebgen after the attack took place on Tuesday morning.
Controversial expansion
Tesla wants to double the size of its Berlin plant - which is its only one in Europe - a plan which some environmentalists object to because it would involve chopping down nearby trees.
Around 100 people are camping in a forest near the factory, protesting against its expansion.
However those green activists have distanced themselves from what has happened.
One group, which calls itself Robin Wood, told the BBC it had "nothing to do with the fire".
