Yvonne Lee - All Headline News Staff Reporter

The large dog was sniffing trees and barking at squirrels sitting in the branches, when they suddenly descended and attacked him, reports BBC News.

"They literally gutted the dog," local journalist Anastasia Trubitsina told the Komsomolskaya Pravda newspaper.

"When they saw the men, they scattered in different directions, taking pieces of their kill away with them."

A shortage of food may have prompted the squirrels to attack, although scientists debunk this theory.

Local scientist Mikhail Tiyunov said it was the first he had ever heard of such an attack.

He said while squirrels without sources of protein might attack birds' nests, the idea of them chewing at a dog to death was "absurd".

"If it really happened, things must be pretty bad in our forests," he said.