Russian border guards say they are taking Greenpeace's "Arctic Sunrise" protest ship to the port of Murmansk after armed officers boarded the vessel and locked up at least 25 environmental activists.
A spokeswoman for the Murmansk region's border guards said on September 20 that the vessel's captain had been questioned and a full investigation will take place when the ship reaches port.
Russia's Federal Security Service (FSB), which controls the country's Border Guard Service, has accused the ship's captain of carrying out "unlawful activities."
The regional unit of Russia's Investigative Committee said it was considering bringing charges of piracy, which can carry a sentence of up to 15 years in jail.
Vladimir Chuprov, Russia Arctic program chief for Greenpeace, described the raid to the media: "About eight people in masks and special equipment rushed onboard the ship shouting, 'We are from the FSB.' They gathered the crew on the raft, threatening them with weapons, put them on their knees, and kept them there for a certain period of time. They also conducted a search and took away all the computers and all data-storage devices."
Tatyana Vasiliyeva, a spokeswoman for Greenpeace Russia, told RFE/RL that the group could not confirm if or when the ship will be taken to Murmansk, since contact with the "Arctic Sunrise" had been interrupted since late on September 19.
"We don't know anything more about the vessel, what is going on. It's unclear whether [the border guards] will tow them to Murmansk," Vasiliyeva said.
"We cannot speak to the members of the crew. We know that they are in the cabin and are [only] allowed to leave for the toilet or cigarettes because that's why they aren't responding to telephone calls."
Border guards said the rest of the ship's journey would take three days.
The Russian Foreign Ministry earlier accused the group of "aggressive and provocative" behavior.
Russian news agencies say that special operations units of the border guards seized the "Arctic Sunrise" late on September 19 after four Greenpeace activists tried to board Gazprom's Prirazlomnaya oil platform in the Pechora Sea to prevent it from drilling.
Greenpeace said it would stage protests on September 20 outside Russian embassies and the offices of state-run oil giant Gazprom worldwide.
The environmentalist group is campaigning against the surveying of oil and natural-gas fields on the Arctic shelf in order to preserve the region's unique environment.
But the prospect of wider access to energy resources as global warming gradually melts the sea ice has sparked a race between Russia, Norway, and Canada to search for oil and gas in the region.
With reporting by AFP and Interfax