Finnish authorities seized a Russian-linked ship in the Baltic Sea on Thursday, suspected of damaging an undersea power cable between Finland and Estonia a day earlier.
The incident has heightened fears in Europe of a Russian hybrid war targeting infrastructure in the Baltics and beyond.
What happened in Finland?
Finnish police said that coastal workers boarded an oil tanker in Finnish waters early Thursday.
Authorities named the vessel Eagle S, and said it was registered to the Cook Islands in the South Pacific.
When it was built, the ship was en route from Saint Petersburg in Russia to Port Said in Egypt, according to online shipping tracking website MarineTraffic.
According to MarineTraffic, the ship belonged to the Caravella company from the United Arab Emirates.
It crossed the line at 10:26 GMT on Wednesday – the same time the blackout was reported.
The 170km (106-mile) Estlink-2 undersea power cable, which carries electricity between Estonia and Finland, broke on Wednesday. Finnish broadcaster Yle reported that the cable was thought to have been cut by the ship's anchor.
In addition, four telecom cables were disrupted, including three between Finland and Estonia and one between Finland and Germany.
Finland has launched a criminal investigation into whether a Russian-bound ship was involved in the cable break. The United States has said it will help with the investigation.
“We are closely cooperating with our allies and are ready to support their investigations,” said a spokesman for the US National Security Council.
NATO has also criticized this. The general secretary of the union, Mark Rutte, wrote on his X account that: “We are following the investigation of Estonia and Finland, and we are ready to provide further assistance.”
The European Union's foreign policy chief, Kaja Kallas, said it was the “latest in a series of suspected terrorist attacks”.
Kallas added that the ship “is part of Russia's shadow fleet, which threatens security and the environment, while supporting Russia's war budget”.
What is a cruise ship?
The ship, or ship, is described as an old ship with unknown ownership, carrying Russian oil, which was acquired to avoid Western sanctions and the cheap prices offered by the West for Russian oil transported by sea, amid Moscow's war in Ukraine .
After the recent incident on the Baltic Sea, the Estonian government called an emergency meeting. Estonian Prime Minister Kristen Michal said repairing the damaged cable could take up to seven months.
Michal told a press conference that these photo vessels are “helping Russia get money to support the Russian invasion”.
Estonia and the military have taken action at sea to protect the Estlink 1 undersea power cable, said Estonian Minister of Defense Margus Tsahkna on Friday.
What are some of the most recent hybrid warfare events?
Hybrid Warfare refers to the use of conventional and unconventional tactics to create instability in countries without making it look like a conventional war.
Mixed battles includes assassination plots, election interference and destruction of vital infrastructure such as submarine cables. NATO allies have criticized Russia for its heavy use of hybrid warfare. It is very difficult to determine whether an event is a hybrid war.
On November 17 and 18, two cables were cut in the Baltic Sea, one between Finland and Germany, and the other between Lithuania and Sweden.
Other media outlets, including The Wall Street Journal, reported that the Chinese-flagged carrier Yi Peng 3, which had left the Russian port of Ust-Luga, appeared to be passing cables at the same time each cable was cut.
Germany's defense ministry said authorities must have suspected the attack was malicious, but did not say who was responsible, or provide evidence.
“The Baltic Sea region has been taking measures to deal with cable cutting,” Keir Giles, senior adviser at London-based think tank Chatham House, told Al Jazeera.
He said methods like investigations can be a deterrent to future destruction because there is a risk of property being seized.
He also said that an armed attack on Finland or Estonia, as described in Article 5 of the NATO treaty, is doubtful.
Article 5 states that any NATO ally can attack another as an attack on any NATO country. Estonia has been a member of NATO since 2004, and Finland joined the alliance in 2023 amid the Russia-Ukraine conflict.
In 2022, there were two eruptions Nord Stream gas pipeline which goes from Russia to Germany. No one has claimed responsibility for the explosion and Berlin is still investigating the incident.