OXNARD, California - A Metrolink train derailed Tuesday morning after it collided with a tractor trailer on the tracks in Ventura County, California, injuring at least 30 people, officials said.

The VC Line 102 train, which was headed southbound to Los Angeles, hit the truck around 5:45 a.m. near 5th Avenue and Rice Street in Oxnard, according to the Ventura County Fire Department.

"For some reason there was a tractor trailer on the tracks there at Rice Avenue and Train 102 collided with it," Scott Johnson of Metrolink told CBS Los Angeles.

The truck caught fire and four train cars derailed.

It was unclear if there were any fatalities.

Metrolink reports that all Ventura County trains will experience extensive delays due to the accident.

The cause of the accident is under investigation.