A chartered bus carrying students collided with a semitrailer Wednesday night on icy roads in north-central Illinois, sending at least 18 people to the hospital, authorities said. None of the injuries appeared life-threatening.

Ten ambulances were sent to the accident site on Interstate 39, said Illinois State Police spokeswoman Paris Ervin. At least two vehicles including the bus were involved in the collision, which occurred on an icy road, although it was too early to speculate on a cause, Ervin said.

Students went to three area hospitals, said a dispatcher at the LaSalle County sheriff's office. Fifty-six students were on the bus, but the dispatcher did not know how many people were injured.

Staff at St. Margaret's Hospital in Spring Valley were treating 13 students, a nursing supervisor said. She declined to describe the nature of the injuries but said none was life-threatening.

Five students had arrived at Illinois Valley Community Hospital in Peru by 10 p.m., but a nursing supervisor said none of them was injured.

A woman who answered the telephone at St. Mary's Hospital in Streator declined comment.

The interstate was closed Wednesday night. Lostant is located about 40 miles north of Bloomington.