Russian authorities on Friday continued to hold the crew of the Greenpeace icebreaker Arctic Sunrise incommunicado a day after security forces stormed the vessel, the international environmental group said in a statement.

The group said they have not been in contact with the ship and its crew, which appear to be heading west toward Russian territorial waters, for almost 24 hours.

On Wednesday, activists from the Arctic Sunrise sent five vessels to the Prirazlomnaya oil platform, which is operated by the Kremlin-controlled OAO Gazprom (MCX:GAZP), triggering gunfire -- at least 11 shots were fired -- from the Coast Guard at the Arctic Sunrise, it was reported.

"Due to the refusal of the Arctic Sunrise captain to halt the unlawful activity, the administration took a decision to stop the ship. The Coast Guard was forced to fire warning shots four times from an artillery cannon onboard a vessel," the Russian Federal Security Service said.

Yesterday, in a dramatic series of tweets, the crew tweeted to the world that Russian authorities rappelled onto the ship from a helicopter with guns drawn.

The crew members locked themselves in the communications room, where they had been tweeting up until the ship lost contact with Greenpeace.  

BREAKING: Helicopter hovering above Arctic Sunrise, rope dropping down. We think the Coast Guard is boarding us. #SaveTheArctic â€” Arctic Sunrise (@gp_sunrise) September 19, 2013

Russian authorities onboard with guns. They are breaking into the comms room now. #savethearctic


They're almost in the room. This could be our last tweet for awhile. Thanks for all your support, don't stop now! #Savetharctic


No contact to the Arctic Sunrise anymore. Greenpeace will continue to tweet updates here #SaveTheArcrtic


Greenpeace has not received any formal confirmation of charges, and according to the group, activists have been denied access to legal counsel. More than 20 Greenpeace offices are organizing protests at Russian embassies around the world today.

“The real threat to the Russian Arctic comes not from the crew of the Arctic Sunrise but from Gazprom, one of the most reckless oil companies in the world today,” the statement read.