Greenpeace has dispatched its campaigning vessel Rainbow Warrior III to block the Mikhail Ulyanov, an oil tanker owned by Russia's state oil firm Gazprom.

Making its way to Rotterdam, Mikhail Ulyanov is loaded with the first cargo of oil from the Prirazlomnaya platform, Russia's first offshore production unit in the Arctic.

According to the Barents Observer, the Rainbow Warrior III has left port in the Netherlands. And the green group said it expects the two vessels will meet at some point.

Greenpeace has been a vocal critic of drilling for oil in the Arctic, which it says will lead to oil spills and could wreak havoc on the Arctic's fragile ecological system.

In an interview with Tradewinds News, the environmental group refused to disclose further actions, saying only "something big is about to happen". "Unfortunately [we] can't let you know exactly just yet as that might scupper our plans," said a spokeswoman for Greenpeace.

It will not be the first time Greenpeace has staged a large-scale protest against Gazprom.

Twenty-eight activists and two journalists were jailed for two months by Russian authorities after they attempted to board the same drilling platform in September.
They were released before the Sochi Winter Olympics, but the vessel "Arctic Sunrise" is still in the custody of Russian authorities.