"In some parts perhaps not a single one of the seal cubs born in the past few weeks will survive," the WWF said in a statement.

It said hundreds of the roughly 1,500 ringed seal cubs born this month and last month were in danger.

Seal cubs spend the first weeks of their lives in burrows dug in the ice sheet but if that melts, they find themselves in the ocean before they have built up a fat layer that will enable them to survive, WWF's Cathrin Muenster said.

"When the ice melts too fast, the cubs end up in the ice water before they have their insulating fat layer, and they die painfully of hunger and cold."

The WWF said there was less ice in the Arctic this winter than at any point in the past 300 years.

It said the seal cubs most at risk were those along the southwest coast of Finland, the Gulf of Finland and the Gulf of Riga, but warned that the layer of pack ice in the Gulf of Bothnia between Sweden and Finland is also thinner than usual.

WWF estimates that there are between 7,000 and 10,000 ringed seals in the Arctic, compared to 180,000 a century ago.

Scientists say the Arctic is heating up twice as fast as the rest of the planet. The phenomenon also puts at risk polar bears who could become extinct as their natural habitat melts away.

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