The Eagle S – a tanker ship carrying Russian oil and suspected of severing the Estlink 2 power cable running under the Baltic Sea between Finland and Estonia – was reportedly brimming with spy equipment.

Police in Finland are investigating what they called "grave sabotage" and have taken command of Eagle S, an oil tanker believed to belong to a so-called shadow fleet of ageing tankers which seek to evade Russian sanctions.

Finnish authorities have boarded a foreign oil tanker escorted into its waters after disruptions on a subsea power link and several data cables.