Earlier this month, a Scotch cross ewe was killed on Brithdir land near Llanberis in what the farmer said was the third such attack within three months.

A number of incidents have been reported in both Eryri and on Anglesey - in the past month, a lamb was attacked in the Marian-glas area while a ewe suffered serious injuries in Dinas Dinlle.

But North Wales Police say many such attacks are going unreported to both officers and farmers, resulting in unnecessary suffering and livestock deaths.

PCSO Rhys Evans from the force's rural crime team said: "Any such attack needs to be reported immediately to the police or the farmer, in order that the animal can be treated to avoid unnecessary suffering."

"Sheep will hide for a long time following a chase which is why the farmer needs to get there as soon as possible."

"When sheep are spread out over a vast are, they’re often not checked for days or weeks at a time, which is why it is important that any attacks are reported promptly."

PCSO Evans is also urging anyone walking around livestock in the countryside to keep their dogs on leads and to keep close control of them.

"Allowing a dog to chase livestock can cause significant stress, fear and injury – and it is a criminal offence," he added.

"A dog’s owner is the only person who can prevent an attack from happening, and you may have to pay the ultimate price if you cannot control your animal. Responsible dog ownership is key in tackling these awful incidents."