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.

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

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.

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

Lion1, which runs through the Baltic Sea between Finland and Germany, has been severed. The telecommunications connection has been disrupted, Yle reports. The Finnish state-owned company Cinia, which builds fiber optic networks and provides telecommunications services,