The death toll from the Friday head-on train collision near Los Angeles has gone up to at least 17 as emergency crews found new victims early Saturday.

More victims are feared trapped in the wrecked Metrolink commuter train while about 135 people were injured with about 85 of them in serious or critical condition.

250 firefighters and 200 policemen remained on the scene in the San Fernando Valley before dawn Saturday.

"This is the worst accident I've ever seen," Los Angeles Mayor Antonio Villaraigosa said. "Clearly the injuries are going to mount and so are the fatalities."

Metrolink spokeswoman Denise Tyrrell said the Metrolink train left Union Station in downtown Los Angeles and was headed northwest. The trains were on the same track when they collided at about 4:30 p.m. in the Chatsworth area of the San Fernando Valley.
The cause of the crash is under investigation to be headed by the National Transportation Safety Board.

Prior to Friday, the worst disaster in Metrolink's history occurred on Jan. 26, 2005, in suburban Glendale when a man parked a gasoline-soaked SUV on railroad tracks. A Metrolink train struck the SUV and derailed, striking another Metrolink train traveling the other way, killing 11 people and injuring about 180 others. Juan Alvarez was convicted this year of murder for causing the crash.