This is the horrifying moment an American Bully attacked a dog that was drinking from its water bowl.

CCTV footage shows the owner lounging on a hammock while browsing through his phone when the thirsty white canine stood in front of the container for a drink.

This triggered the territorial grey Bully to lunge and attack the animal in Saraburi, Thailand, on August 28.

Upon seeing this, the pet owner immediately jumped up and grabbed the leash of his dog, trying to stop it from hurting the pooch.

The commotion also caused a brown Bully to join in and gang up on the white dog. However, a Siberian Husky rushed in to intervene, allowing the hapless dog to escape.

The owner said that his American Bully was feeling possessive over its water bowl, which caused it to attack the other dog without hesitation.

American Bullies are known to display territorial behaviour over objects they own if not properly trained or socialised.