Pit Bull
A toddler was mauled and killed by a pack of pit bulls in US north Bryan County, Georgia (Reuters)

An American toddler has been mauled to death by a pack of pitbull terriers in Bryan County, Georgia.

A 21-month-old girl, whose name has not been revealed, was attacked in the backyard of her house by seven dogs owned by her family, Bryan County deputy sheriff James Beatty said.

Police received an emergency call after the little girl's grandmother, who was asleep in the house, was woken up by the noise of the dogs.

The woman looked out of the window and saw the horrifying scene of her granddaughter being mauled by seven of the nine family dogs.

Police said she rushed out to scare off the dogs but was too late, Savannah Morning News reported.

"When we got here and spoke to EMS [Emergency Medical Services], they told us she was already cold. There was nothing they could do," Beatty said.

Beatty said it is not clear why the toddler was left alone in the yard with the dogs.  

The deputy sheriff suggested that the little girl's older brother, 12, might have taken her out to play and then forgot to bring her back inside or she might have crawled out through the dog flap.

"All the dogs had access to the house - nine dogs in all," Sheriff Clyde Smith said.

"She habitually played with the dogs, all of them. But they dragged her all over the yard. Something turned them on her. We don't know what."

The killer dogs were put down at the scene. The other two, which are of a different breed, were spared.

The incident came just days after 14-year-old Jade Anderson was believed to have been killed by a pack of out-of-control dogs at a house in Greater Manchester.