Berlin Blackout Linked to Vulkangruppe Attack
Longest blackout since World War II.
Vulkangruppe claimed responsibility for the attack.
Attack targeted fossil fuel industry.
Vulkangruppe described action as self-defense and international solidarity.
Berlin Mayor Kai Wegner condemned the attack.
Mayor vowed to prosecute perpetrators.
Restoration efforts began on Jan 7, with full service expected by Jan 8.
1 week ago