A group of armed and masked men have issued a video in which they vow to start hunting bears in France’s Pyrenees mountains following attacks on sheep.

Brown bears, a protected species, were blamed for the deaths of about 450 sheep who tumbled over cliffs while being chased by bears in two separate incidents this summer.

The threat to hunt them marks an escalation of a bitter dispute between farmers and conservationists over the predators. They were re-introduced into south-western France from Slovenia in the 1990s after hunters had all but wiped out native Pyrenean bears.

The video, filmed outdoors at night and sent to news organisations, shows about 30 men holding shotguns or hunting rifles, their faces hidden by balaclavas.