Staff members took the gun and gave it to police upon arrival, FOX 2 reported. 

Principia head of schools Merry Sorrells told the station the entire school community was notified about the incident. 

"We wanted our parents to know that there was never a risk or a threat to any of our students or community members," Sorrels said. 

EL PASO FOOD COURT MALL SHOOTING BEGAN AS A CONFRONTATION BETWEEN TWO GROUPS

Town & Country Police Chief James Cavins said his department believes the incident was "inadvertent" and that the student did not intend to harm anyone. Nor was there any neglect found on the part of the student’s parents, KMOV reported. 

Schools are on high alert after a 6-year-old first grader at a Virginia elementary school shot a teacher during an altercation in the classroom last month, leaving her with "life-threatening" injuries and renewing calls from parents for greater classroom safety and oversight. 

Last week, a 6-year-old boy in North Carolina was caught with an unloaded 9mm firearm in his backpack after another student alerted a teacher. The teacher was able to secure the backpack and remove the child from the classroom.