FRANKFURT - German police said Wednesday they suspected a "deliberate act" damaged an electricity substation, the latest in a string of incidents involving critical infrastructure.
The overnight incident in Bergheim in North Rhine-Westphalia state came day after a sabotage attack involving explosives near a power plant southeast of Berlin.
Police were called on Tuesday evening when a short-circuit knocked out some lines at a substation in Bergheim, though no power cuts were reported.
"We are not assuming a technical failure but a deliberate act," a local police spokesperson said, describing the incident as a "disruption".
Amprion, the grid operator that runs the affected substation, added that "external interference" was highly likely.
Energy company RWE said five power-generating units at two of its coal-fired plants in the region were knocked out by the disruption at the substation.
Three of the units were expected to go back online later Wednesday while the two others should be restarted at the weekend.
The disruption came a day after improvised explosives, resembling large fireworks, were used in a sabotage attack on a substation in eastern Germany, about 100 kilometres (60 miles) southeast of Berlin.
Several electricity lines were damaged but there was no major blackout.
Far-left militants have claimed responsibility for several acts of sabotage in and around Berlin, and the country is also on high alert for plots linked to Russia because Germany strongly backs Ukraine in its war with Moscow.