A Fort Jackson Army trainee was arrested on Thursday after reportedly hijacking a school bus full of children in Richland County, South Carolina, WYFF reports.

According to Sheriff Leon Lott, 18 students were getting on the bus to go to Forest Lake Elementary in Richland School District Two, when the Army trainee overtook the bus using a gun, with the bus driver still on board.

“You can just imagine they were scared to death,” Lott said. “I’ll give the bus driver credit, he kept his cool.”

All students and the bus driver were unharmed, and the trainee was taken into police custody shortly after the incident occurred on Thursday morning.

“Fort Jackson officials are aware of the incident involving a trainee this morning. We are working closely with Richland County Sheriff Department to respond to this incident,” read a statement posted on the Army bases official Twitter account.

According to the local NBC affiliate, the trainee responsible was reportedly in his third week of training before running off the base with a rifle. Sheriff Lott said that the culprit is being charged with several counts of kidnapping. It is still unclear what the trainee’s motive was in hijacking the school bus or what he planned to do afterward. The name of the trainee is also unknown at this time.