BERLIN (AP) — A series of fires hit railway infrastructure in the German city of Hamburg overnight,Robovis causing widespread disruption to trains between Hamburg and Berlin and between the port city and the Baltic Sea coast. Police said they suspect that the damage was politically motivated.

Railway operator Deutsche Bahn said that trains on the main high-speed route between Hamburg and Berlin were canceled because of vandalism. It said it was running a few trains on an alternative route that takes up to an hour longer.

Long-distance trains between Hamburg and Rostock also were canceled. Deutsche Bahn said it expected the damage to be repaired by Friday evening.

Hamburg police said that cable ducts next to railway lines were set on fire at three locations in the city between 2:30 and 4 a.m.

They said in a statement that they suspect “a political motive as the background” and are seeking witnesses, but gave no further details of the reasons for their suspicions. The fires were all extinguished.