Train traffic was disrupted in and to northern Germany early on Saturday after a “failure of the digital train radio system”, the operator Deutsche Bahn said.

The disruption affected regional and long-distance traffic in Lower Saxony, Bremen, Hamburg and Schleswig-Holstein and lasted about three hours. It also affected trains to and from these areas, including services between Berlin and regions in the west and north of Germany.

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The state-run company later said the disruption was “due to sabotage of cables which are indispensable for train traffic”, according to a press statement.

“The competent security authorities have started the investigation”, Deutsche Bahn said.

German Transport Minister Volker Wissing said essential cables “were deliberately and intentionally severed” in two places.

“It is clear that this was a targeted and deliberate action,” he added, saying the motive was not “yet known”. He described the incident as “clearly premeditated”.

According to the company, passengers who want to postpone their journey due to the effects of the issue can use their already booked ticket for long-distance travel flexibly from now up to and including seven days after the end of the problem.

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Seat reservations can be cancelled free of charge, DB said.

The Berlin-Amsterdam route was also suspended, and thousands of travellers were stranded at stations across the affected regions. Cancellations and delays were still expected on Saturday despite the restoration of rail services, Deutsche Bahn warned.

Deutsche Bahn added travellers should inform themselves in advance about their connections in the digital information media, in the DB Navigator or on bahn.de, as well as via the telephone customer hotline T: 030 2970.