On November 22, the UN maritime tribunal ruled that the Greenpeace ship and its crew, facing trial for a protest against Arctic oil drilling, must be allowed to leave Russia, but Moscow declined to take part in the case lodged by the Netherlands and has suggested it would defy the ruling.

Russian investigators have now barred the Greenpeace activists from leaving the country despite an international court ruling, the organisation has said.

Russia's Federal Investigative Committee rejected a request to seek exit visas for the 26 foreign environmental activists from 17 countries who were among the 30 arrested after an attempt to scale Russia's first offshore oil platform in the Arctic in protest.

The activists face up to seven years in prison on hooliganism charges. They were, however,  released on bail last month by courts in St Petersburg and hoped to be able to go home pending trial or further action by investigators that requires their presence.

A reduction in Arctic summer ice cover has become more intense in recent years, culminating in a record low of 3.4 million square kilometres in 2012 – 18 per cent below the previous recorded minimum in 2007 and 50 per cent below the average in the 1980s and 1990s. Land ice is also retreating and permafrost is melting.

The retreating ice brings easier access to natural resources such as gas and oil, thus prompting increased human activity that may threaten the already fragile ecosystems and wildlife.

"What we are seeing is that the melting of ice is prompting a rush for exactly the fossil fuel resources that fuelled the melt in the first place," Achim Steiner, the UNEP Executive Director has stated.

Putin last week ordered his military to increase its focus on the resource-rich region Arctic, where Russia is vying for control with Canada, the United States, Denmark and Norway.

The rush for resources prompted by an apparent acceleration in sea ice melt calls for caution and effective governance to avoid damage to the fragile Arctic environment, according to the UN Environment Programme´s Year Book 2013.