Russian authorities are threatening to bring criminal charges against activists aboard a seized Greenpeace vessel in the Pechora Sea to draw attention to the environmental risks of oil extraction in Arctic waters.
The Federal Security Service (FSB) said the Amsterdam-registered ship, "Arctic Sunrise," was being towed to Murmansk but might not arrive until September 23.
It said there were 27 people aboard, including four Russian citizens. There are Canadians and Britons on board, as well.
Russian authorities "are holding 30 of our activists," citing two activists who were arrested days earlier. (There has been no explanation for the discrepancy in figures.)
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.
On September 21, Kremlin administrative chief Sergei Ivanov said the Greenpeace activists had acted "too radically." Speaking in Stockholm, Ivanov said Greenpeace is a well-known organization but he believed their actions in trying to climb onto the "Prirazlomnaya" oil platform in the Pechora Sea resembled "piracy Somali-style."
Greenpeace International strongly rejected the Russian allegations of piracy. In a statement, the group's general counsel, Jasper Teulings, described the accusation as a desperate attempt by Russian authorities to justify the illegal boarding of its ship in international waters.
Greenpeace said armed Russian troops had forcibly boarded and seized the "Arctic Sunrise" on September 19 -- one day after two activists who climbed onto Russia's first Arctic offshore oil platform, owned by Gazprom, were arrested.
WATCH: Greenpeace activists have continued their protests against Gazprom and Russia's Arctic policies:
The crew has been incommunicado ever since the raid, and Russian authorities say they are towing the vessel with its crew to the port of Murmansk.
"The Arctic Sunrise arrived in these icy waters alongside millions of people around the world who oppose Arctic oil drilling," Greenpeace said in a statement
after the seizure, describing the environmental group's #SaveTheArctic campaign. "Together, we wanted to protest peacefully against Gazprom's plans to become the first company to pump oil from the icy Arctic ocean."
The FSB has rejected the environmental campaign group's assertion that the ship was in international waters when it was seized.
Russian authorities have also suggested that a structure the activists approached the oil platform resembled a bomb. Greenpeace, which advocates nonviolence in its environmental efforts, called that accusation "ludicrous" and said its "safety pod" is "a big foam tube" used to "shield the activists from things like water cannons."
Russia, one of five countries bordering the Arctic Ocean, has stepped up the pursuit of energy and other interests in the Arctic in recent years, including planting a Russian flag during an "Arktika 2007" expedition that marked the first time a manned submersible reached the seabed at the North Pole.
Based on reporting by Reuters, AP, and RFE/RL