Train services between Berlin and Hamburg were interrupted on Friday due to a suspected sabotage incident.
Railway cables were set on fire in three different locations in the early hours of the day, German authorities told local media.
Germany's railway operator Deutsche Bahn said the incident led to long delays and the cancellation of nearly two-thirds of the high-speed train services between Berlin and Hamburg.
"The resumption of train services between Hamburg and Berlin will probably only be possible on Saturday morning," a spokesperson of the railway operator told Bild daily.
A far-left group claimed responsibility for the sabotage act, and Hamburg police said that the incident was being investigated as a politically motivated attack.
"We sabotaged arteries of capitalist infrastructure in Hamburg," the far-left group said in a letter posted on a popular left-wing website.
"We show our solidarity with the communities worldwide affected by industrial destruction and those who are behind bars for the fight against capitalism," the group said.
