Some 80 Greenpeace activists, among them two Czechs, on Thursday tried to prevent the delivery of the first oil from Russia's new Arctic drilling platform reaching port in Rotterdam. Their attempt to stop the oil-tanker Mikhail Ulyanov failed after Dutch police intervened giving the tanker clear passage to port. The activists were briefly detained aboard their own ship to allow the tanker to enter the port unhindered. Police said the activists had reneged on an agreement they had made with the harbour authorities not to interfere physically with the ship during their protest. Greenpeace is opposed to drilling in the Arctic Sea which it says risks causing a catastrophe in a fragile ecosystem.