Witnesses said they watched in panic Sunday as a double-decker tourist bus on San Francisco's Haight Street caught fire.
According to the San Francisco Chronicle, it happened around 10:30 a.m. near Shrader Street. Witnesses report people ran after the bus to tell the driver the bus was on fire.
An ambulance crew arrived and helped unload the bus. No one was injured.
Investigators are trying to determine the cause of the fire.
