Germany and Finland say they are "deeply concerned" after an undersea cable linking the countries was severed.The rupture of the 1,170km (730-mile) telecommunications cable - which is being investigated - comes at a time of heightened tension with Russia.

An unexplained fault in an undersea telecommunications cable linking Finland and Germany has disrupted communication services, the company that runs the link said Monday. The C-Lion1 cable that connects Helsinki to Rostock in Germany was built and is operated by Cinia,

Authorities in Finland say a submarine data communications cable across the Baltic Sea between Finland and Germany has broken and the cause for the disruption is being investigated

A data cable linking Germany and Finland along the seabed has been broken and may have been cut off by an outside force, according to the

Cables connecting Finland with Germany, and Lithuania with Sweden, have been disrupted, just weeks after the United States warned that it had detected increased Russian military activity around key undersea cables.

Telecommunications between Finland and Germany faced disruptions following damage to the C-Lion1 undersea cable, essential for connectivity to Central Europe.

The C-Lion1 submarine cable between Germany and Finland is no longer working. The repair could take days, the cause is unclear.

All telecommunications running on the submarine cable have been cut off. A cybersecurity expert tells Yle that the cable break is likely to be intentional.

And last year, Finnish authorities investigated a Chinese ship named NewNew Polar Bear after it was suspected of deliberately damaging submarine cables in the Baltic Sea. According to Samuli Bergström, a director of Finland's National Cyber Security Center, however, “it is certainly possible” the cable broke on its own.