Firefighters are investigating the cause of a destructive fire inside an Escondido fast-food restaurant early Thursday.
Fire swept through the McDonald's located on Ash and Valley Parkway just after midnight.
Flames were estimated to climb 100-feet into the air from the restaurant’s roof.
Employees believe the fire started in the air conditioning system. Fire crews were on scene investigating.
Only minor injuries were reported.
The fire is being investigated, but officials said it is likely the cause was accidental.