BERLIN (AP) — German police said Monday they’re examining the possibility of a political motive in the suspected sabotage of a railway communication system over the weekend that brought trains to a standstill across the northwest of the country.

Officials say cables were severed deliberately in a Berlin suburb and in Herne in western Germany, sites that are 440 kilometers (275 miles) apart.

Trains in the northwestern states of Hamburg, Schleswig-Holstein, Lower Saxony and Bremen were halted for nearly three hours on Saturday morning. Railway operator Deutsche Bahn said that was necessary because a digital train radio system failed.

Authorities opened an investigation into suspicion of dangerous interference with rail traffic.

Police in the western city of Bochum said Monday that their state protection unit is conducting the investigation “because a political motivation is also being examined.” They didn’t elaborate on what that potential motivation might have been.