An act of “sabotage” targeting communications infrastructure was to blame for major disruption on the German railway network on Saturday, operator Deutsche Bahn said. “Cable sabotage” was the cause of the breakdown, which led to a three-hour suspension of train services throughout northern Germany , a spokesman for the company told AFP. There was damage to the GSM-R, a radio network used for communication on the railway, Der Spiegel reported, quoting security sources. The cables could have been cut “in two places”, it added. Any action against the cable would require “certain knowledge” of the rail system, the Bild daily said, adding that federal police were investigating. Traffic was completely interrupted for about three hours because of “a breakdown in the digital radio system for the trains”, before being restored, according to Deutsche Bahn. DB said on its Twitter page that rail traffic was still patchy in northern Germany on Saturday afternoon after coming to a standstill for several hours due to an issue with radio communications. The disruptions affected rail services through the state of Lower Saxony as well as the city states of Bremen and Hamburg, with a knock-on effect to international rail journeys to Denmark and the Netherlands. DB become increasingly known in recent years for train delays and cancellations due to its creaking infrastructure. But the disruption on Saturday raised alarm bells after Nato and the EU last month stressed the need to protect critical infrastructure, after what they called acts of “sabotage” on the Nord Stream gas pipelines . The German government has also stepped up protection of its critical infrastructure.