Four people were killed, including minors, and several others were injured after a vehicle crashed through a building hosting an after-school camp in Illinois, striking multiple people inside and outside the structure.

The incident took place around 3:20 p.m. Monday in the small town of Chatham, about 12 miles south of the state capital, Springfield. Those killed are believed to be between the ages of 4 and 18, Illinois State Police said in a statement. Several others were taken to hospitals and one person was transported to a medical facility via helicopter.

The driver of the vehicle — which struck the building’s eastern side before exiting through its west wall — appeared uninjured and was taken to a hospital for evaluation, state police said. Authorities did not publicly identify the driver.

Illinois Gov. JB Pritzker (D) called the crash an “unspeakable tragedy” and said state police and the Chatham Police Department are investigating.

“I am horrified and deeply saddened by the deaths of children and numerous injuries in Chatham this afternoon,” he said in a statement late Monday.

“Parents said goodbye to their kids this morning not knowing it would be the last time,” Pritzker added. “My heart is heavy for these families.”

Chatham has a population of about 14,500, according to Census Bureau figures.

State police, Chatham police and the governor’s press office did not immediately respond to a request for comment.