Did a Russian ‘shadow ship’ cut the Finland-Estonia undersea Baltic cable? 

Finnish authorities seized a Russia-linked ship in the Baltic Sea on Thursday, on suspicion that it damaged an undersea power cable between Finland and Estonia a day earlier.

The incident has intensified fears in Europe over a Russian hybrid war targeting critical infrastructure in the Baltic and beyond.

What happened in Finland?

Finnish police said in a statement that the coastguard crew boarded an oil tanker in Finnish waters early on Thursday.

Authorities named the vessel as the Eagle S, and said it was registered in the Cook Islands in the South Pacific.

When it was detained, the ship was sailing from Russia’s Saint Petersburg to Port Said in Egypt, according to online marine tracking website, MarineTraffic.

According to MarineTraffic, the ship was owned by United Arab Emirates-based vessel management company, Caravella.

It crossed the cable at 10:26 GMT on Wednesday – the same time a power outage was reported.

The 170km (106-mile) Estlink-2 undersea power cable, which carries electricity between Estonia and Finland, broke on Wednesday. Finnish broadcaster Yle television reported that the cable is suspected to have been severed by the ship’s anchor.

Additionally, four telecom cables were disrupted, including three between Finland and Estonia and one between Finland and Germany.

Finland has launched a criminal investigation to assess whether a Russia-linked ship was involved in breaking the cable. The United States has said that it will help with the probe.

“We are coordinating closely with our allies and stand ready to support their investigations,” said a spokesperson from the US National Security Council.

NATO has also condemned the incident. The alliance’s Secretary General Mark Rutte posted on his X account: “We are following investigations by Estonia and Finland, and we stand ready to provide further support.”

The European Union foreign policy chief Kaja Kallas said the incident was “the latest in a series of suspected attacks on critical infrastructure”.

Kallas added that the ship “is part of Russia’s shadow fleet, which threatens security and the environment, while funding Russia’s war budget”.

What is a shadow ship?

A shadow ship, or ghost ship, is described as an ageing ship with obscure ownership, carrying Russian fuel, acquired to circumvent Western sanctions and Western-imposed price caps on Russian oil being transported by sea, amid Moscow’s war on Ukraine.

After the recent Baltic Sea incident, the government of Estonia convened an emergency meeting. Estonian Prime Minister Kristen Michal said repairs to the damaged cable could take as long as seven months.

Michal told a news conference that these shadow vessels “are helping Russia to earn funds that will aid Russian hybrid attacks”.

Estonia’s armed forces have launched a naval operation to protect the Estlink 1 undersea power cable, said Estonia’s Foreign Minister Margus Tsahkna on Friday.

What hybrid warfare incidents have taken place recently?

Hybrid warfare refers to the use of conventional and unconventional methods to create instability in countries without making it seem like an all-out war.

Hybrid warfare includes assassination plots, election interference and damaging critical infrastructure such as undersea cables. NATO allies have accused Russia of extensively using means of hybrid warfare. It is very difficult to prove when an instance is an act of hybrid warfare.

On November 17 and 18, two cables were severed in the Baltic Sea, one between Finland and Germany, and another between Lithuania and Sweden.

Some media, including The Wall Street Journal, reported that the Chinese-flagged bulk carrier Yi Peng 3, which had departed from the Ust-Luga port in Russia, appeared to pass over the cables at about the same time each cable was cut.

The German defence minister said that officials had to assume that it was an act of sabotage, but did not say who was responsible, or provide evidence.

“The Baltic Sea states have been steadily taking more decisive measures against cable cutting,” Keir Giles, a senior consulting fellow at the London-based Chatham House think tank, told Al Jazeera.

He said measures such as investigations could serve as a deterrent against future sabotage activities because there is a risk of cargo being seized.

He added that an armed attack against Finland or Estonian infrastructure, such as that described in Article 5 of the NATO treaty is unlikely.

Article 5 decrees that each NATO ally must treat an attack on any ally as an attack against every NATO country. Estonia has been a NATO member since 2004, and Finland joined the alliance in 2023 amid the Russia-Ukraine war.

In 2022, explosions occurred along two Nord Stream gas pipelines which run from Russia to Germany. No one has claimed responsibility for the explosions and Berlin is still investigating the incidents.