The environmental group Greenpeace says that Russian authorities have boarded their ship which is in the Arctic to protest against oil drilling.
The group is protesting offshore oil exploration conducted by state oil company Rosneft and ExxonMobil in the Russian section of the Arctic Ocean off western Siberia.
Greenpeace said in a statement on Monday that Coast Guard officials boarded the ship without permission after the group launched inflatable boats with banners reading "Save the Arctic" near an oil exploration vessel working for Rosneft.
Russia has denied permission for the Greenpeace ship to enter the Kara Sea, but the ship entered the waters on Saturday morning.
Campaigners have been warning of high risks of oil blowouts and spills in this pristine and hard-to-reach area.