A gruesome video has caused outrage as it showed a group of fishermen using an anchor to kill a spotted deer swimming in a river near their boat in Argentina.

The herd of deer were swimming in the Parana River in an attempt to find solid ground following recent floods in the region on Wednesday, 19th October.

But the group of anglers from the province of Corrientes who were sailing down the river decided to change from fishing to hunting big game and bag an animal instead.

They then quickly changed the rod for a rope and began throwing it towards a deer swimming along the boat.

When the poor animal got hooked on the rope, one of the fishermen began pulling it to the boat with all of his strength.

The unidentified man then began to hit it on the head with an anchor until the animal showed no more signs of life.

Spotted deer (Axis axis), also known as chital or cheetal, are a deer species native to the Indian subcontinent.

They were reportedly introduced by European ranch owners in Argentina at the beginning of the 20th century.

Unlike the marsh deer (Blastocerus dichotomus), which is a species native to South America, spotted deer are not threatened with extinction.

But they are constantly subjected to excessive hunting for their meat, leather and antlers.

Media did not report whether the fishermen have been reported to the police