MOSCOW, September 24 (RAPSI) – Federal investigators have launched a maritime piracy case days after Greenpeace activists attempted to board a Gazprom oil rig in the Barents Sea, Russian Investigative Committee’s spokesman Vladmiri Markin told journalists Tuesday.

“All participant of the attack on the platform will face criminal charges, regardless of their nationality, Markin added.

The Arctic Sunrise ship was seized by Russian border guards Thursday in international waters, within Russia's exclusive economic zone, a day after two Greenpeace activists scaled the Prirazlomnoye drilling rig in the Pechora Sea, the southeastern part of the Barents Sea. Greenpeace claimed that the ship was seized at gunpoint.

Russian investigators said the vessel was involved in “piracy,” a crime punishable by up to 15 years in prison, and that an investigation would be conducted to consider the allegations. The ship is expected to arrive in the Russian port of Murmansk on Tuesday.

Media reports said some 30 people, including six Britons and one American, were on board the vessel.

The platform, owned by Gazprom Neft Shelf, a subsidiary of Russian energy giant Gazprom, is the first ice-resistant stationary oil platform in the world set to produce offshore Arctic oil.

Greenpeace and other environmental groups oppose drilling for oil in the Arctic because they say that it is currently impossible to sufficiently clean up potential oil spills in the region, and that such drilling cannot be economically viable without state subsidies.