Arson attack on Berlin power grid was meticulously planned: Minister

German Interior Minister Alexander Dobrindt believes the fire that left tens of thousands of Berliners without power was a targeted attack meticulously prepared, reported dpa.

Repair work is ongoing after two high-voltage pylons in south-eastern Berlin went up in flames early on Tuesday, resulting in major damage to important supply lines.

Some 20,000 households in the German capital were still without electricity on Wednesday as a result of the attack, which is believed to have been carried out by left-wing extremists.

A claim of responsibility that surfaced on Tuesday said the action targeted the "military-industrial complex" in a science park in Berlin's Adlershof neighbourhood.

Dobrindt said it was striking "that these distribution stations were obviously selected deliberately and not at random."

"This means that preparations had to be made and analyses carried out to determine where to attack the network in order to cause as much damage as possible."

The minister said police were still unable to say whether the letter, published on left-wing platform Indymedia, was authentic.

In any case, it was clear that the attack had been carried out by a group open to using violence, he added.