Greenpeace climate campaigner and protest organiser Simon Boxer said the Arctic Sunrise was being towed to the port of Murmansk, and was expected to dock tomorrow morning.
"We heard that people were being lined up on the helicopter deck, were made to go down on their knees with hands behind their head. They had guns pointing at them, they were then taken to the dining area of the ship and were held there."
Greenpeace's legal team has advised against publicly releasing the names of the activists on Arctic Sunrise, but Mr Boxer said family members of those on board - including the two New Zealanders - were being kept well informed of the situation.
The organisation's legal team were also awaiting the vessel's arrival in Murmansk, he said.
"We will be there to try and get the people released ... [and] check out how the crew are."
Activists on the Arctic Sunrise were last in contact with members of Greenpeace two days ago, Mr Boxer said.
Information from New Zealand's Foreign Affairs ministry indicated they were all safe, he said.
"It's absolutely clear that the people should be released. It was a peaceful protest. The ship was in international waters. What Russia has done is illegal."
Mr Boxer said the Russian Embassy in Wellington had stopped answering calls from protesters, and there had been no response to written communications.
Russian officials have told international media the activists could fact terrorism or piracy charges. Mr Hughes, who helped deliver Greenpeace's ice sculptured message this morning, described the allegations of piracy as "patently ridiculous".
"Ultimately, we've got a couple of Kiwis who have stood up for a safe climate, stood up for the Arctic environment, facing an armed boarding of a peaceful protest ship.
"I think the storming of a protest vessel outside Russian territorial waters is more akin to piracy then putting a protest banner."
