SACRAMENTO -- Two children, including an 8-year-old Oakland boy, were among four people killed when a car collided with a minivan on Highway 50 over the weekend, authorities said.

California Highway Patrol spokesman Officer John Frizzell said that on Saturday night a Toyota Prius driven by Sheng Kun Su, 38, of Oakland, crossed the center line on Highway 50 near Placerville and struck a Toyota Sienna minivan "broadside." The crash also injured five other people.

Three people in the Prius including Su, a woman and a boy, were killed in the crash. A fourth passenger in the Prius -- 10-year-old Elly Aili Su -- survived the crash with moderate injuries, said El Dorado County Sheriff's Office Sgt. Jim Byers.

Byers said 39-year-old Shu Zhen Zhao, the mother of the children; and 8-year-old Shawn Su, all from Oakland, died in the crash.

The sole survivor in the Prius was transported to Marshall Hospital to be treated for her injuries. She was released to extended family in the Bay Area, Byers said Sunday.

A 4-year-old passenger in the van also died. Sheriff's officials identified her as Nora Elizabeth Temple, 4, of Pollock Pines.

Four others in the van, a 35-year-old woman who was the driver, a 51-year-old male passenger, and two twin 1-year-old boys, suffered minor to moderate injuries, Byers said.

Weather conditions at the time of the crash were clear.

"We don't know what caused the Prius to cross into oncoming traffic," Frizzell said Sunday. "There's an infinite number of possibilities."

Investigators have pulled computers from both vehicles that would indicate how fast they were going at the time of the crash, but collecting that information would probably take days, Frizzell said.

Highway 50 at that location has a speed limit of 65 miles per hour, Frizzell said.

The Associated Press contributed to this report. Contact Natalie Neysa Alund at 510-293-2469. Follow her at Twitter.com/nataliealund.