A four-year-old boy has been killed by a falling bullet that was fired into the air during New Year's Eve celebrations in the US.

Marquel Peters was playing a video game inside a church in the state of Georgia when the bullet pierced the roof and hit him in the head, local media reported.

He collapsed on the floor alongside his parents, bleeding, and was taken to hospital where he died.

"I saw his Nintendo game fall on the floor, and I heard a sound and I heard him scream a little bit and I looked around and all I saw was blood coming from his head," Marquel's mother Nathalee Peters told a local TV station."

"He was my only child ... I miss him, I loved him, he was so sweet," she told Sky News.