The Central Criminal Police has not yet found evidence that Russian special services are behind severing the Finland-Estonia underwater cable. However, the incident prompted NATO to launch the Baltic Sentry mission.

The Baltic Sea region is on high alert as fears grow that Russia could target undersea cables as part of a wider campaign of so-called "hybrid warfare".

Nato countries have stepped up patrols to protect critical underwater infrastructure in the Baltic Sea, which is bordered by eight countries, and other waters. A Royal Navy submarine was ordered to surface last November close to a suspected Russian spy ship which was loitering over undersea infrastructure in UK waters.

NATO is deploying eyes in the sky and on the Baltic Sea to protect cables and pipelines that stitch together the nine countries with shores on Baltic waters

Shipping firms may need to pay a fee to use the Baltic Sea, one of the world's busiest shipping routes, in order to cover the high costs of protecting undersea cables, Estonia's defence minister said on Wednesday following a spate of breaches.

Russia has condemned the Western alliance for ramping up its naval presence in the so-called 'NATO lake' after alleged sabotage by Moscow-linked vessels.

TradeWinds reported this week that Bulgarian bulker owner Navibulgar admitted that one of its ships may have cut an undersea cable in the Baltic Sea over the weekend, but dismissed sabotage claims.

This week, the Estonian authorities noted provocative ideas and gestures, potentially leading to a sharp aggravation of the military-political situation in the Baltic Sea.

In addition to the patrols, Defence Minister Hanno Pevkur said countries are weighing other measures to protect cables, including installing sensors to detect anchors dragged across the sea floor or constructing casings or walls around the cables.

An overnight Ukrainian drone attack hit Russia’s Andreapol oil pumping station, part of the oil export route via the Baltic Sea port of Ust-Luga, causing a fire and oil products to leak, said a source in the Security Service of Ukraine on Wednesday.