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ETNA, Ohio (NewsNation) — At least six were killed and 18 others injured Tuesday after a charter bus carrying students from a high school was rear-ended by a semitrailer on an Ohio highway, according to police.

The charter bus was transporting a driver and 54 students and chaperones from Tuscarawas Valley High School in Tuscarawas County, the Ohio State Highway Patrol said in a news release Tuesday night.

The accident occurred shortly before 9 a.m. on Interstate 70 West in Licking County, near the Smoke Road underpass. According to the Ohio State Highway Patrol, the bus was traveling west on I-70 when it was hit by a commercial semitrailer traveling in the same direction.

At least five vehicles were involved in the crash, according to the National Transportation Safety Board.

Three of the passengers on the bus were pronounced dead on the scene. They have been identified as John W. Mosely, 18, of Mineral City; Jeffery D. Worrell, 18, of Bolivar; and Katelyn N. Owens, 15, of Mineral City.

The driver of the bus and 15 students were transported to a local hospital.

All three people in one of the passenger vehicles involved were also pronounced dead on the scene. They have been identified as Dave Kennat, 56, of Navarre; Kristy Gaynor, 39, of Zoar; and Shannon Wigfield, 45, of Bolivar.

The driver of another passenger vehicle was hospitalized, as was the driver of a second commercial vehicle. The driver of a third commercial vehicle was released on the scene.

Ohio Gov. Mike DeWine said he is with the highway patrol and expressed his sympathies for all those involved in the crash.

“Fran and I are praying for everyone involved in the bus crash east of Columbus today. It is our worst nightmare to have a bus full of children involved in such a terrible crash, and it is certainly the worst nightmare that families and schools can endure,” he said.

Those aboard the charter bus were en route to the Ohio School Boards Association Conference in Columbus, the Tuscarawas Valley School District said in a statement.

“Right now, our focus is on getting in touch with our Tusky Valley families who had loved ones on the bus and providing support to our entire school community. Our Trojan family is strong, and it will take that strength and love to get throughout these coming challenging days,” said Tuscarawas Valley School District Superintendent Dr. Derek Varansky.

The conference was canceled after organizers learned of the crash.

“Given this devastating news, we have canceled our conference. Right now, our focus is on providing support to Tuscarawas Valley. That includes making grief counselors from our trade show available,” said Jeff Chambers, the association’s director of communication services.

The American Red Cross of Central and Southern Ohio said it fulfilled a request for more blood from one hospital in the area, sending 30 units to a hospital in the Mount Carmel Health System, per Marita Salkowski, regional communications director.

A center was set up at a United Methodist Church in Etna for bus passengers not in need of medical attention to go to and contact loved ones, she said.

Numerous emergency responders were at the scene, and Ohio Department of Transportation cameras from the area showed smoke coming from the crash site. The highway was closed in both directions, and numerous traffic delays were reported.

At 10:30 a.m., two school buses were seen arriving at the scene, escorted by police. Several dozen people boarded the buses, which drove away about 20 minutes later, NewsNation affiliate WCMH reports.

Mickey Lymon, an investigator with the Licking County Coroner’s Office, said they had been called to the scene but deferred other questions to the state police.