RALEIGH, N.C. — Raleigh police are investigating a report that two young students were sexually assaulted on a school bus.

Investigators said the bus from Dillard Drive Elementary in Raleigh was taking students home on Interstate 40 Monday when the alleged incidents occurred. They said two boys, ages 10 and 11, are facing juvenile charges in connection with an incident involving a 5-year-old girl and 7-year-old boy.

On Tuesday, a parent notified school officials, who later contacted police.

"It was some sort of contact amongst the individuals on the bus that would arise to what would be classified as a criminal offense," said Sgt. Stacy Deans, of the Raleigh Police Department.

"Nobody at the school level was notified of the incident prior to it being brought to our attention by a parent. Once we were notified, our director of security personally investigated it and, subsequent to that, immediately contacted police and we are cooperating with them right now," said Michael Evans, spokesman for Wake County schools.

Officials said the bus driver was not aware that any assaults had occurred until after they were reported.

Investigators would not say what exactly happened on the school bus because everyone involved in the case is a juvenile. The two suspects have been placed in a secure juvenile facility.