At least 13 people have died after a multi-vehicle crash in California, about 10 miles away from the U.S.-Mexico border, authorities said Tuesday. The crash occurred near State Route 115 in Imperial County, California. “We believe there was 27 passengers in this S.U.V. that struck a semi truck full of gravel,” Judy Cruz, the emergency room managing director at the El Centro Regional Medical Center, told reporters. The cause of the accident is still under investigation. Dr. Adolph Edward, the CEO of the El Centro Regional Medical Center—where some of the crash victims were taken—told The New York Times that he believed most of the victims were undocumented.

Omar Watson, chief of the California Highway Patrol’s border division, later clarified that there were 25 people inside the S.U.V. and 12 died at the scene. One more person died in hospital, bringing the total to 13—two less than the death toll erroneously cited by hospital officials earlier on Tuesday.