Police say a 3-year-old Tennessee boy shot his 18-month-old brother in the head.

The Coffee County Sheriff's Department said the little boy shot his sibling with a .25-caliber automatic pistol in a home Tuesday afternoon in the community of Hillsboro, which is about 70 miles southeast of Nashville.

The 18-month-old was transported to a local hospital. His condition was unknown late Tuesday.

Sgt. Danny Ferrell told The Associated Press that investigators are still trying to determine how the 3-year-old got access to the weapon.