An act of “sabotage” targeting communication infrastructure was to blame for a major disruption on the German railway network.
Federal police are investigating the incident, Minister of the Interior and Community Nancy Faeser said on Saturday, adding the motive for it was unclear.
The apparent attack brought train travel to a standstill throughout northern Germany and the capital Berlin at the start of the weekend, before it was fixed a few hours later.
The disruption raised alarm bells after NATO and the European Union last month stressed the need to protect critical infrastructure after what they called acts of sabotage on the Nord Stream gas pipelines.
“It is clear that this was a targeted and malicious action,” Minister for Transport Volker Wissing told a news conference.
Operator Deutsche Bahn (DB) earlier said the disruption was caused by a technical problem with the digital train radio communication system.
“Sabotage to cables – which were vital for train traffic – meant Deutsche Bahn had to stop trains running in the north this morning for nearly three hours,” DB said.
Countless travellers in the region were stranded at railway stations. Queues rapidly built up at mainline stations, including Berlin and Hanover, as departure boards showed many services being delayed or cancelled.
A security official said there were a variety of possible causes, ranging from cable theft – which is frequent – to a targeted attack.
Omid Nouripour, leader of the Greens party, which is part of Chancellor Olaf Scholz’s federal coalition, said anyone who attacked the country’s critical infrastructure would receive a “decisive response”.