A militant conservation group claimed Wednesday that up to 50 pilot whales have been killed in the first traditional whale hunt of the year in the Faroe Islands, but authorities there defended the practice and slammed the activists.

A pod of 100-150 pilot whales was spotted off the northeastern island of Svinoy, where several boats had chased them 11 kilometres (6.8 miles) towards the village of Hvannasund, claimed the Sea Shepherd group.

"The whales were forced to beach, and slaughtered by locals," the group said in a statement, citing local media reports as saying between 30-50 pilot whales had been killed.

Pictures on the website of Faroese newspaper Nordlysid showed the sea turning red with blood as the whales were killed.

But a spokesman for the Faroese government spokesman, Pall Nolsoe, said: "Whaling is a natural part of Faroese life and pilot whale meat and blubber are a cherished supplement to households across the islands.

"Whaling in the Faroe Islands is conducted in accordance with international law and globally recognised principles of sustainable development."

And he added: "The illegal and potentially dangerous actions by activists from the Sea Shepherd Conservation Society, combined with attempts to spread deliberately misleading information .. continue to be the hallmark of this group's activities."

Sea Shepherd has traditionally tried to stop and document the hunt, but earlier this year a law was passed to allow the government to ban ships from entering Faroese waters "in order to prevent any disruption of... pilot whale drives and other lawful activity in these waters."

Sea Shepherd said it had "modified its tactics" this year and that it would target the Faroese whale hunt "in the judicial and political arenas, in commerce, in industry and as always in the media" instead.

In August last year, a ship carrying 21 activists from the group trying to disrupt the traditional hunt was refused entry by Faroese authorities based on "immigration legislation and in the interests of maintaining law and order."

During the hunt, the three-to-six metre (10-to-20 foot) sea mammals are driven by a flotilla of small boats into a bay or the mouth of a fjord before being killed by hand -- a practice that many locals defend as a cultural right.

The whale meat and blubber are consumed by locals and considered delicacies.

The Faroe Islands are a self-governing archipelago belonging to Denmark in the North Atlantic Ocean.