Houston: An 8-year-old boy accidentally shot and killed his 5-year-old sister while wounding his 4-year-old brother in yet another shooting incident in the US involving children.

The tragic incident occurred when the siblings were alone in an apartment in Jacksonville, Florida, Sheriff's Office Chief Chris Butler said. Their mother had left the three kids by themselves when the shooting happened on Saturday, Butler told The Florida Times-Union. He said somehow the eldest boy got a gun from somewhere and fired a single shot.

The bullet hit his sister, killing her, and striking the younger boy who sustained a non-life-threatening gunshot wound, Butler said. Butler said the 4-year-old is being treated at the hospital, and is expected to make a full recovery.

In 2016, within a space of about four months at least 23 toddler-involving shootings had taken place in the US.

"We have no reason to believe this (shooting) was an intentional act...We believe, in the absence of any other information being developed, that unfortunately this is a tragic unfortunate accidental shooting," Butler said. He said the Sheriff's Office is consulting with other agencies including the office of State Attorney Melissa Nelson and Florida Department of Children and Families Child Protection Team in the ongoing investigation.

Police responding to a 911 call found the two children shot inside the apartment. Jacksonville Fire and Rescue Department personnel administered emergency life-saving procedures but were unable to save the girl, Butler said. No charges had been filed yet. Although in the past people have been charged with leaving a gun accessible to children, Butler said, it is too early in the investigation to say whether that that might happen in this case.