Washington, March 12 (IANS): Five people, including three children, were killed after a school bus collided with a semi-truck on a highway in Rushville, about 91 km northwest of the US Illinois state capital, Springfield.

Addressing a press briefing, Illinois State Police said the crash happened on Monday around 11:30 a.m. (1730 GMT) when the school bus heading east on US Route 24 crossed the center line into the westbound lanes for an "unknown reason" and collided with the semitruck carrying sand, Xinhua news agency reported.

Both vehicles erupted into flames after the collision. All four people aboard the school bus, including the driver and three children -- one five years old and two three years old -- as well as the driver of the semitruck were pronounced dead at the scene.

Following the incident, the school district canceled school on Tuesday and Wednesday.

The cause of the crash is under investigation.

More details are awaited.