A simple childish fight over a puppy led an 11-year-old boy to shoot and kill his eight-year-old neighbor in the US state of Tennessee, the girl's grieving mother said.

Latasha Dyer said her daughter was playing outside when the boy asked to see her puppy. Little McKayla said "no" and shortly after was shot in the chest.

"When we first moved to White Pine, the little boy was bullying McKayla," Latasha Dyer told WATE 6 news in a video posted on the station's website Sunday.

"He was making fun of her, calling her names, just being mean to her. I had to go the principal about him and he quit for a while and then all of a sudden yesterday he shot her."

Dyer was overcome with emotion as she spoke to the local television station from the front steps of her mobile home in White Pine, Tennessee.

"I want her back in my arms, this is not fair, hold and kiss you're babies every night because you're never promised the next day with them," she said. "I hope the little boy learned his lesson because he took my baby's life -- and I can't get her back."

She described her daughter as "a precious little girl, she was a mommy's girl, no matter how bad of a mood you were in she could always make you smile."

Jefferson County Sheriff G.W. "Bud" McCoig said the boy has been charged with first degree murder and was being held in a juvenile detention center.

"Our prayers are with the families that are involved in the tragic incident," he said at a press conference.

The boy was inside his home when he shot the girl with his father's single-shot 12 gauge shotgun at about 7:30 pm Saturday, McCoig said.

"The two were neighbors and in this neighborhood all the children would play together and knew each other and all attended school together," he said.

McCoig declined to release any further details, explaining that five other children live in the boy's home and two other children live in the girl's home and "we're trying to protect them, as much as they've been hurt by this tragedy."