This is the astonishing moment a guard dog drags a 200lb concrete block down the road to chase off a stray.

CCTV footage captured the tense scene as an uninvited visitor cautiously circled the home in Yichun, eastern China, on August 12, apparently on the lookout for food.

One of the resident guard canines can be seen chained to a large, heavy slab, seemingly unable to move, giving the guest the confidence to inch closer.

But just moments later, the silence is shattered by the harsh scraping of stone on pavement, as a second guard dog suddenly charges forward at full speed, dragging its own weigh-down block behind it.

Startled by the unexpected counterattack, the stray immediately bolts, with the black guard pooch astonishingly gaining ground as the clip comes to an end.

The dog's owner, Mr Yu, told local media that the animal is not aggressive, but was simply acting out of territorial instinct.