General Mark Rutte says the military alliance will step up patrols in the Baltic Sea area as Finnish investigators work to establish whether a ship linked to Russia sabotaged undersea cables there this week.

NATO Secretary-General Mark Rutte on Friday said the alliance will increase patrols in the Baltic Sea region after Finland seized an oil tanker suspected of having damaged undersea power and internet cables this week.

This latest episode of cable damage adds to a series of similar disruptions or suspected sabotage acts in the strategically important Baltic Sea.