The undersea fiber optic cable between Germany and Finland has stopped working and may have been deliberately cut by an unknown person, according to officials.

The 729-mile (1,173 km) C-Lion1 cable, which runs under the Baltic Sea from Helsinki to Rostock, went offline just after 02:00 GMT on Monday.

The outage was reported by Finnish state-controlled cybersecurity and telecom company Cinia.

Chief executive Ari-Jussi Knaapila said a physical examination had not yet been carried out but its sudden nature suggested it had been completely cut off by an external force.

Germany And FinlandForeign ministers said they were “deeply concerned” and that it “immediately raises suspicions of deliberate damage”.

The joint statement included the following: “Our security in Europe is threatened not only by Russia’s aggressive war against Ukraine, but also by hybrid warfare by malicious actors.

“Protecting our shared critical infrastructure is vital to our security and the resilience of our societies.”

Cinia said “corrective measures” were being taken and a repair ship was being prepared.

Mr Knaapila told reporters it could take about five to 15 days to repair the damage to the fiber optic cable.

He said the damage occurred at the southern tip of the Swedish island of Öland and Cinia was working with authorities to investigate.

The cable connects central European telecom networks to Finland, other Scandinavian countries and Asia.

Last year, another sunken gas line and several telecommunications cables were seriously damaged in the Baltic Sea.

A Chinese container ship dragging its anchor has been identified as the prime suspect by Finnish police. But they did not say whether they thought the damage was intentional.

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Natural gas pipeline two years ago Russia to Germany – Nord Steam – also damaged by explosions.

Many suspected Moscow of foul play, but German authorities are still investigating the incident.