Greenpeace says its lawyers are seeking the immediate release of 30 people who were arrested last week for attempting to board Russia's only oil production platform in the Arctic.
Greenpeace International Executive Director Kumi Naidoo said Friday the detentions are "like the Russian oil industry itself, a relic from an earlier era." Naidoo said the activists were in prison for "shining a light on Gazprom's recklessness."
Gazprom, Russia's state-controlled natural gas monopoly, owns the oil rig that was the target of the Greenpeace protest.
The environmental group says it is will stage "solidarity protests" Saturday in cities around the world.
On Thursday, a court in the Arctic port city of Murmansk denied bail for U.S. national Pete Wilcox, the captain of the Greenpeace ship Arctic Sunrise, along with 20 other crew members and activists from Russia and at least 10 other countries, and a Russian photographer.
The court ordered that the 22 detainees be held in prison for two months pending an investigation into their roles. Several other activists were ordered held for 72 hours.
Russian authorities are determining whether the activists can be charged with piracy, among other offenses. If found guilty of piracy, they could be jailed for up to 15 years.
President Vladimir Putin said Wednesday the Greenpeace campaigners are not pirates. However, he added that, in attempting to board the oil rig, Greenpeace violated international law and endangered the well-being of both the workers on the rig and the activists.