PAYNE COUNTY, Oklahoma - Two 17-year-old students at Classen SAS in Oklahoma City were killed early Friday morning in Payne County when another vehicle crashed into their broken-down van on a highway.

Three girls were in a van heading westbound on State Highway 51 around 1 a.m. when their Chevrolet van broke down. Three people – a 30-year-old man and two teenage boys – began pushing the van while the girls remained inside the vehicle.

The Oklahoma Highway Patrol says as the van was being pushed, 29-year-old Michael Reed of Perkins was also driving westbound on State Highway 51. He crashed into the van.

Two passengers in the van – 17-year-old Dajia Brown and 17-year-old Karla Duenes – were pinned inside the vehicle for two hours while emergency crews tried to free them. They died from their injuries. The driver of the van, 16-year-old Sofia Gabrielson, was flown by EagleMed to OU Medical Center. She's in serious condition with a head injury.

Brown was in the 11th grade at Classen SAS, and Duenes was in the ninth grade. Gabrielson is a student in the 10th grade.

Oklahoma City Public Schools spokesperson Tierney Tinnin says the girls were not participating in any school-related function at the time of the crash. Grief counselors are at the school Friday to help students and staff deal with the tragedy.

"The staff and students at Classen School of Advanced Studies are grieving the loss of two students and hoping for a full recovery for the third student involved in the accident," Tinnin said.

Of the three pedestrians who were pushing the van, two were treated at Stillwater Medical Center and released. The third pedestrian was not hurt.

Reed, the driver of the second car, was not seriously injured. He was treated and released from a hospital.

OHP doesn't know yet why Reed crashed into the van. He did not appear to be impaired, and the road conditions were fine.

Reed was wearing a seatbelt. No one in the van was wearing seatbelts.