ATWATER, Calif. (AP) — A charter bus veered off a central California freeway before dawn Tuesday and struck a pole head-on, killing five people and sending at least five others to hospitals, authorities said.

The pole of a highway exit sign sliced the unmarked white bus carrying about 30 people nearly in half lengthwise, photos and video show.

"The pole went through the center of the bus, and that's where the injuries were sustained," California Highway Patrol Officer Moi Onsurez told The Associated Press.

Emergency workers climbed in through the windows to pull passengers out. The five injured were airlifted to hospitals, Onsurez said, but he did not have information about any additional injuries or the cause of the single-vehicle crash.

The bus was heading from Southern California to Sacramento on State Route 99 when it crashed around 3:30 a.m. between the cities of Atwater and Livingston, Onsurez said.

Atwater is a city of 28,000 people in Merced County, about 65 miles northwest of Fresno.

The northbound lanes of the freeway were closed during the investigation.