The European Union and Nato have escalated their responses following damage to the Estlink 2 power cable between Finland and Estonia.
The EU has proposed new sanctions targeting Russia's so-called "dark" or "shadow" fleet, while Nato has pledged support for Finland and Estonia in protecting critical infrastructure. Meanwhile, Estonia has deployed a naval vessel to secure subsea cables in the Baltic.
EU targets Russian "dark" fleet
The EU suspects that the damage to Estlink 2, a key subsea power cable linking Finland and Estonia, may have been caused by the oil tanker Eagle S.
Finnish authorities have boarded and detained the Eagle S, a Cook Islands-flagged oil tanker linked to Russia's so-called "dark fleet", a network of tankers operating without insurance recognised by western countries.
The vessel was observed to slow down when in the vicinity of the cable when it was damaged.
According to the EU, the shadow fleet threatens security and the environment, while simultaneously funding Russia's war chest.
"We propose additional measures, including sanctions targeting this fleet," said Kaja Kallas, the EU's High Representative for Foreign Affairs and Security Policy.
Earlier this month, the EU approved sanctions against approximately 50 Russian oil tankers linked to the shadow fleet. Efforts to safeguard subsea cables, including enhanced international cooperation, are also being intensified.
Nato pledges support
Nato Secretary General Mark Rutte after a discussion with Finnish President Alexander Stubb has said that Nato will "increase its presence in the Baltic Sea".
"I spoke with Alexander Stubb about the ongoing investigation, led by Finland, into the potential sabotage of undersea cables. I expressed my full support and solidarity. Nato will increase its presence in the Baltic Sea," Rutte wrote on social media platform X.
Rutte also reaffirmed the alliance's commitment to assisting its member states.
"Nato stands behind its allies and condemns all attacks on critical infrastructure. We are monitoring the investigations initiated by Finland and Estonia and are prepared to provide additional support," Rutte wrote.
Although Rutte did not elaborate on the specifics of Nato's potential assistance, Estonian officials have confirmed ongoing discussions with Nato regarding measures to protect vital infrastructure.
Estonia deploys naval patrol
In response to the incident, Estonia has deployed the Raju, a naval patrol vessel, to safeguard the Estlink 1 power cable, which remains operational.
Estonian Defence Minister Hanno Pevkur announced the move on X, adding that Estonia is prepared to protect its energy links with Finland "by military means if necessary."
Pevkur also revealed that Estonia has proposed collaboration with Finland on securing the cables and suggested that other Nato allies, such as Sweden, Germany or Poland, might join the effort.
According to Estonian public broadcaster ERR, the Raju departed Tallinn earlier today and is currently patrolling in the centre of the Gulf of Finland.
Investigation underway
The Estlink 2 power cable was damaged on Christmas Day in Finnish waters. The Finnish Border Guard along with the Special Intervention Unit Karhu from the Helsinki Police Department detained the Eagle S and is investigating its potential involvement in the incident.
Finnish and Estonian authorities continue to lead the investigation into the cause of the damage.