Four college softball players were killed and a dozen others were injured when their bus was involved in a crash on an Oklahoma freeway, officials said Friday.

The crash occurred around 9 p.m. local time when a semi truck crossed over a median into oncoming traffic north of Ardmore, Oklahoma and collided with the bus, Oklahoma Highway Patrol Captain Ronnie Hampton said.

Three of the North Central Texas College softball players were pronounced dead at the scene, and a fourth player died after being taken to a local hospital, Hampton said.

The rest of the students were rushed to local hospitals, nine by ambulance and two by helicopter, Hampton said.

“We ask for your prayers at this time for our softball team,” the community college said in a statement.

The truck driver was taken to a local hospital, Hampton said. The softball team’s coach, who was driving the school bus, refused treatment at the scene.

The conditions of the injured people were not immediately clear.

Both vehicles were severely damaged, but fires did not break out, Hampton said. A homicide investigation was underway and the National Transportation Safety Board is expected to arrive Saturday to investigate, Hampton said.

The crash occurred about 12 miles north of Ardmore.