In this photo from August 2013, Port Colborne, Ont. native Paul Ruzycki, chief mate of the Greenpeace vessel Arctic Sunrise,
Credits: Will Rose / Greenpeace
The Canadians were among 25 crew members arrested aboard the Arctic Sunrise after they protested Gazprom's Arctic oil drilling operations.
The Canadian government said it's been in touch with Russian authorities.
"Consular officials have inquired with Russian officials on the situation. Due to the privacy act, we are not able to share any more information on this matter," said Beatrice Fenelon, a spokeswoman from the Department of Foreign Affairs.
The regional unit of Russia's Investigative Committee said it was considering bringing charges of piracy against the activists.
"It is now over 12 hours since Greenpeace International has had any contact with the ship, which appears to be heading west towards the Russian territorial waters," said a release from Greenpeace on Friday, adding that "the activists have been denied access to legal or consular assistance."
Among those arrested are Paul Ruzycki of Port Colborne, Ont., and a Canadian woman whose name has not been released.
Ruzycki's sister, Patti Stirling, said her family is overwhelmed.
"I can only joke (badly) that maybe (Russian President Vladimir) Putin thought the rainbow on the bow of the boat signified a gay rights campaign underway and ordered the commando attack," she said, adding the Russian action was overkill against unarmed non-violent protesters.
The Arctic Sunrise had been stationed near a Russian coast guard vessel that was holding two activists who had tried to board the Gazprom-owned oil rig Prirazlomnaya on Wednesday.
Gazprom is the largest extractor of natural gas and one of the largest companies in the world.
Gazprom's International declined to comment.
Russian authorities said Amsterdam-registered ship is being towed to Murmansk, but might not arrive until Monday.
Russia denies Greenpeace's assertion that the ship had been in international waters when it was seized.
Ben Ayliffe, the head of Greenpeace International's Arctic oil campaign, said the safety of activists remains Greenpeace's top priority.
"They have done nothing to warrant this level of aggression and have been entirely peaceful throughout. In our last phone call with the ship, the crew said that their spirit remains high and they have been boosted by messages of support from thousands of people who stand with them to oppose dangerous Arctic oil drilling," he said.
- with files from QMI's Jessica Murphy and Reuters