Environmental activists with Greenpeace Friday occupied one level of the semisubmersible platform Leiv Eiriksson, the world's second-largest rig, as it steamed west at 6 knots in the Sea of Marmara, heading for the Dardanelles and the open Mediterranean, The Guardian reported.
Greenpeace boats approached the vessel and 11 climbers boarded the rig.
"This is Greenpeace, this is Greenpeace. I'm informing you that we have put climbers on your rig. I ask you stop your vessel," Korol Diker, a Turkish Greenpeace campaigner, radioed the rig's captain.
"I do not recognize you," the captain replied, and the Leiv Eiriksson steamed on as the activists made a cradle of rope on the rig's lower level from which to hang banners and a tent.
Greenpeace is expected to shadow the rig as it passes Greece, Italy, France and Spain on its voyage through the Mediterranean and into the Atlantic, the newspaper said.
The platform is scheduled to stop in Britain to pick up supplies before the last leg of its journey to Greenland in June.