Helsinki's energy company says they needed to take delivery of the coal from Russia because it was already agreed in a contract - despite earlier pledges to the contrary.
Protesters in Helsinki climbed onto cranes on a cargo ship in an effort to stop it unloading coal from Russia on Tuesday morning.
Ten activists from Greenpeace Suomi scaled perimeter fences at the Salmisaari port in the Finnish capital and attached themselves to cranes on the Maltese-registered Transbaltic, which sailed from the Russian port of Luga on Monday night.
"The ship has four cranes they use for unloading and we managed to climb on three of them so basically it stopped most of the unloading," says Matti Liimatainen from Greenpeace Suomi.
The coal is being delivered to Helsinki's city-owned power company Helen, which had announced in March it would stop importing coal from Russia to use at its power station in Helsinki -- but now says that it's honouring contracts already in place, with this unlikely to be the final shipment.
"We will be responsible for our contractual obligations with Russian coal suppliers until the end of the contracts. Upon expiration of the agreements, the procurement of coal from Russia will end," the company said in a statement.
"The problem I have is that one month ago Helen sent out a press release saying from now on they won't be procuring coal from Russia anymore because of the situation in Ukraine," Greenpeace Suomi's Matti Liimatainen explains.
"Somehow I think this is quite a typically Finnish thing, we are so bureaucratic and so bloody honest if we have an agreement we should fulfil it. Even if Russia is a country which doesn't fulfil human rights agreements," he tells Euronews.
The protesters were removed from the cranes by firefighters, and dock workers were able to continue unloading the Transbaltic's cargo of coal.
Helsinki Police say they detained nine people at the dock.