Germany’s defense minister said damage to two fiber-optic cables on the sea floor appeared deliberate, but a culprit was not known.

The damage of two undersea internet cables in the Baltic sea must be seen as an act of sabotage, German defence minister Boris Pistorius has said. A pair of fibre-optic communications cables were severed on Sunday and Monday, in an incident which “immediately raises suspicions of intentional damage”, Finland and Germany said in a joint statement.

Germany’s defense minister says officials have to assume that damage to two data cables under the Baltic Sea, one of which ends in Germany, was caused by sabotage — though he says they have no proof at present.