Firefighters were at the Tesla plant on Tuesday morning to check its safety
Tesla halted production at its car factory in the German capital, Berlin, on Tuesday morning after a suspected arson attack nearby.
An electricity pylon close to the plant caught fire, causing power outages in the factory and nearby towns.
Environmental activists who have been protesting against the site’s expansion have denied responsibility for the fire.
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.
“The rule of law will react to such an act of sabotage with the utmost severity,” said Interior Minister for Brandenburg state Michael Stuebgen.
However, he cautioned against “premature speculation” over who was responsible for the suspected arson.
There are currently around 100 environmental activists camping in the forest near the factory, protesting against its expansion.
Robin Wood, one of the environmental groups in the forest, told the BBC it had “nothing to do with the fire”.
Tesla wants to double the size of its plant – which is its only one in Europe – but the protestors are against this as it would involve chopping down nearby trees.
Protestors have set up treehouses in the forest near the factory
The Tesla factory currently makes around 500,000 cars a year – the Elon Musk-owned company wants to double that.
“We are currently unable to say when production can be expected to resume,” Tesla said in a statement given to the AFP news agency.