Five people, including three children, were killed Monday after a school bus and semitruck collided on a highway in western Illinois, authorities said.

The bus was traveling eastbound on Illinois Route 24 when it crossed the center line into the westbound lanes "for an unknown reason" and into the path of a semitruck carrying sand, Illinois State Police Troop 6 Captain Jody Huffman said at a news conference. Both vehicles were set ablaze in the crash. The crash happened around 11:30 a.m. in Rushville, a community of about 3,000 roughly 60 miles west of Springfield.

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All four people aboard the Schuyler-Industry Schools bus — three children and the driver — as well as the driver of the semitruck, were killed.

"There’s not really words at this time that can be said," Schuyler County Sheriff Bill Redshaw told reporters. "When you have a loss of life like this, it’s devastating."

He said the tragedy hit the small, close-knit community particularly hard.

Schuyler-Industry Schools canceled classes Tuesday and Wednesday because of the crash.

"It is with a heavy heart that we announce our school community has lost both staff and students in the traffic incident involving one of our school buses this morning," the school district said in a statement. "Out of respect for everyone involved, no names or further information will be released at this time."

The cause of the crash remained under investigation Monday afternoon. The names of the victims have not yet been released.

Schuyler County Coroner Terry Millslagle said the victims' bodies were being transported to Springfield for autopsies.