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(CNN) — Six people were killed when a passenger bus crashed on an Arizona interstate Friday, the Arizona Department of Public Safety said.
The wreck occurred at 5:27 a.m. on Interstate 10 south of Phoenix when the commercial bus rear-ended a car, according to Arizona Department of Public Safety spokesman Bart Graves.
The bus veered off the road and rolled over, he said. It is unclear what caused the initial collision, Graves said. Two men and four women died, he said.
Fifteen of the 21 bus passengers were transported to hospitals, including five who suffered serious injuries and were taken by helicopter, Graves said. Two 11-year-olds — a boy and girl — are among the injured.
