As many as 1,400 white-sided dolphins were killed in a day as part of a gory hunting ritual in the Faroe Islands, an autonomous Danish territory, sparking an outrage on social media on Tuesday.

Photos showed the heartrending sight of hundreds of Atlantic white-sided dolphins lying slaughtered on the beach.

Sea Shepherd, a charity that campaigns against the hunting of whales and dolphins, described it as a "barbaric practice".

"There is no doubt that the Faroese whale hunts are a dramatic sight to people unfamiliar to the hunts and slaughter of mammals," AFP news agency cited a spokesman of the Faroe Islands government as saying.

"The hunts are, nevertheless, well organised and fully regulated," he said.

Traditionally, the North Atlantic islands — which have a population of around 50,000 people — hunt pilot whales and not dolphins, the spokesman said.

"There are usually a few of them in the 'grind', but we normally don't kill such a large number," said a local television journalist, Hallur av Rana.

The "grindadrap" is a practice whereby the hunters first surround the whales with a wide semi-circle of fishing boats and then drive them into a bay to be beached and slaughtered.

"It looks quite extreme and it took some time to kill them all, while it's usually pretty quick," av Rana said.

According to av Rana, although some 53 percent of the islands' population are opposed to the "grind", there no plans to abolish the practice. The authorities insist it is a sustainable way of hunting.