The Helsinki-Rostock subsea cable that connects Finland to Germany has been severed.

Authorities said an “external impact” likely caused the incident in the early hours of Monday. The 750-mile (1,200km) cable has been damaged in the Baltic Sea, east of southern Sweden, and it appears to have been completely cut as all its fiber connections are down.

Update: A second cable, within 10m of this system was also cut.

Original story continues: The cable is owned and operated by Finnish networking firm Cinia Oy.

When asked whether the cable had been sabotaged deliberately, Ari-Jussi Knaapila, the firm’s CEO, said there was currently “no way to assess” the cause of the incident.

“We can say that such damage doesn’t happen without some kind of external impact,” he said in comments reported by Bloomberg. Knaapila added that a ship's anchor or trawling on the ocean floor could have led to the cable being cut.

OMS Group Sdn’s cable-laying ship Cable Vigilance is being dispatched to the site from Calais, France, to assess the incident and try to repair the damage. This could take between five and 15 days, Cinia said.

Samuli Bergstrom, a director at the National Cyber Security Centre of Finland, told reporters that the incident had not impacted Finland’s Internet connectivity. The country relies on several routes across Sweden, as well as the Helsinki-Rostock cable, for connectivity.

The cable has been operational since 2016. It was laid to help businesses in central Europe connect to data centers based in Finland and other Nordic nations.

Last year, two cables in the Baltic Sea - connecting Finland and Sweden to Estonia - were damaged. The Swedish government said a "partial" break of the cables had occurred, and the incident was repaired within days.

Last week, a Russian spy ship known to surveil subsea cables was escorted from Irish waters.