Russia has replaced piracy charges against 30 Greenpeace activists with hooliganism charges, federal investigators said.
Arctic oil drilling protesters now face seven year punishment instead of a maximum jail sentence of 15 years for piracy.
The Investigative Committee's statement follows a comment by Russian President Vladimir Putin, who said last month that he doesn't think that the Greenpeace activists were pirates.
Greenpeace replied to the court's decision on Wednesday, saying the lesser charge of hooliganism was still "wildly disproportionate".
"We will contest the trumped up charge of hooliganism as strongly as we contested the piracy allegations," Vladimir Chuprov of Greenpeace Russia said in a statement. "They are both fantasy charges that bear no relation to reality."
Greenpeace members on board the Arctic Sunrise, a Greenpeace ship, were seized by Russian authorities in September after activists staged the protest at the Prirazlomnaya offshore oil platform.
The Netherlands has taken legal action against Russia in international maritime court, claiming it had unlawfully detained Greenpeace activists on a Dutch-registered ship.
The Dutch government said it expected a hearing to be held within the next two to three weeks before the Hamburg-based tribunal.
"The Russian side has informed the Netherlands and the International Tribunal for the Law of the Sea... that it does not intend to take part in the tribunal's hearings," the state-run RIA Novosti news agency quoted an unnamed Russian foreign ministry official as saying on Wednesday.
The Russian foreign ministry official told RIA Novosti that Moscow had also informed The Hague "it does not accept" rulings issued by the arbitration court because they may contradict Russia's federal laws.