Two Canadians _ Alexandre Paul of Montreal and Paul Ruzycki of Port Colborne, Ont. _ are among those facing the piracy charge, which can result in a 15-year prison sentence upon conviction.
Frans Timmermans, the Dutch foreign minister, also said Friday he will file suit to recover the Greenpeace ship Arctic Sunrise, which was seized by the Russian government after the protest.
"I feel responsible for the ship and its crew because it's a ship that sails under the Dutch flag," he told reporters in The Hague, Netherlands.
Timmermans said he would file an arbitration suit at the International Tribunal for the Law of the Sea, based in Hamburg, Germany, because it wasn't clear to him whether the ship's seizure was legal. Greenpeace International, which is based in Amsterdam, denies any wrongdoing and describes the charges as absurd.
The Russian Coast Guard seized the ship and crew after a Sept. 18 protest at the platform, which is owned by the Russian state-controlled oil company Gazprom. The activists are being held in the northern Russian city of Murmansk.
"I really want to consult with my Russian colleagues...to get these people freed as soon as possible," Timmermans said. "I don't understand why this could be thought to have anything to do with piracy; I don't see how you could think of any legal grounds for that."
He added he was open to hear the Russian point of view. Russian investigators filed the piracy charges this week.
"Our ship was illegally detained in international waters following a peaceful protest against Arctic oil drilling and we hope that other states, especially the countries whose nationals are among the detained, will support the Netherlands in this commendable initiative," said Greenpeace lawyer Jasper Teulings.
In addition to Russia, the activists hail from 17 other countries: Argentina, Australia, Brazil, Canada, the Czech Republic, Denmark, Britain, Finland, France, Italy, the Netherlands, New Zealand, Poland, Sweden, Turkey, Ukraine and the United States.
The platform, which belongs to Gazprom's oil subsidiary, is the first offshore rig in the Arctic. It was deployed to the vast Prirazlomnoye oil field in the Pechora Sea in 2011, but its launch has been delayed by technological challenges. Gazprom said in September that it was going to start pumping oil this year but did not provide the exact date.
--Associated Press reporter Nataliya Vasilyeva contributed to this story from Moscow.
--With files from The Canadian Press