The Greenpeace icebreaker Arctic Sunrise, which was protesting oil exploration by Rosneft and ExxonMobil in the Kara Sea, was searched, The Financial Times reported.
The Arctic Sunrise entered the Northern Sea Route Saturday morning after Greenpeace unsuccessfully petitioned Russia three times to protest against oil exploration in the region.
The Coast Guard inspection came after Greenpeace launched inflatable boats carrying banners with slogans such as "Save the Arctic," Greenpeace said.
"We refuse to let illegal attempts by the Russian government stop us from exposing dangerous oil drilling in the arctic," said Christy Ferguson, a Greenpeace campaigner on the Arctic Sunrise. "The Russian Arctic National Park is a special place full of rare and threatened arctic wildlife, and faces an infinitely greater threat from reckless oil companies than a fully equipped Greenpeace icebreaker."
The Russian Ministry of Transport said Wednesday Greenpeace was denied access to the area because it failed to provide information about the width of the Arctic Sunrise's protective ice belt.