Greenpeace and Extinction Rebellion campaigners blocked a tanker from delivering Russian oil to Norway on Monday, chaining one of their boats to the giant vessel in a protest against the war in Ukraine, Greenpeace said.

The Ust Luga product tanker is anchored outside Exxon Mobil’s Slagen oil terminal about 70km south of the capital Oslo, according to vessel tracker Marine Traffic.

Activists in a red rubber dinghy chained their vessel to the tanker’s anchor chain as they sought to prevent the offloading of a cargo estimated at 95,000 tonnes of oil, Greenpeace said in a statement.

Several demonstrators were arrested, local police said.

“Oil is not only at the root of the climate crisis, but also of wars and conflicts. I am shocked that Norway operates as a free port for Russian oil, which we know finances Putin’s warfare,” Greenpeace Norway head Frode Pleym said.

The group called on the Norwegian government to ban imports of Russian fossil fuels.

Esso Norway had agreed to buy the oil before the conflict started and does not have plans for further purchases from Russia, a company spokesperson told Reuters.

“Esso Norway fully complies with all Norwegian sanctions and we support the coordinated international efforts to end Russia's unprovoked attack,” Esso said in an emailed statement. The tanker's cargo is used for the blending of marine gas oil.