Ten people were killed and scores injured after a freight train and a commuter train collided head-on outside Los Angeles. The trains, which were heading in the opposite direction, slammed together late on Friday afternoon and officials fear that more bodies could still be trapped under the twisted wreckage. Los Angeles Mayor Antonio Villaraigosa said: "There are at least 10 confirmed fatalities. Confirmed by the coroner's office. That number will likely grow because as you know we are still in the rescue phase. "There are still people that haven't been extricated." The mayor said officials were having a difficult time tallying the number of people injured in the worst commuter train crash in Los Angeles history but that it included dozens and was "probably over 100." Rescuers worked into the night to pry the twisted metal apart and reach victims still trapped and is possible more bodies would be found when the train cars could be moved with heavy equipment. The commuter train held more than 350 passengers and crew. It was not immediately clear why the two trains were on the same track. Passenger Willie Castro said: "I was riding, sitting down, minding my own business when all of a sudden -- boom, people go flying all over the place. "Everyone started screaming. You could hear that everyone was in pain." The commuter train left downtown Los Angeles' Union Station at about 3:30 p.m. The train could carry between 350 and 400 people and officials said it was likely almost full. Police trying to identify the dead, wounded and missing asked family members to come forward. A spokeswoman for Metrolink said the cause of the crash would be investigated.