LOS ANGELES (AP) — Fire officials say a light rail train has collided with a bus south of downtown Los Angeles, injuring at least 13 people.

Fire department spokesman Brian Humphreys says it's unclear how the accident happened. Humphreys says most of the injuries appear to be minor.

The crash involving the Metro Blue Line comes one week after a Metrolink train linking the city to suburbs smashed into a freight train in the San Fernando Valley, about 30 miles northwest of downtown.

The Metro Blue Line is the city's first light rail transit system, running on 22 miles of track within the city.