A natural gas leak may have touched off an explosion at a Canoga Park apartment building, damaging the rear of the structure.

No injuries were reported, said Los Angeles Fire Department spokesman Brian Humphrey.

About two dozen residents, shaken by the loud blast, fled the building at 6530 Independence Ave. and were standing outside when firefighters arrived, Humphrey said.

Firefighters responded shortly before 5 p.m., and the fire was extinguished in about 20 minutes. Officials are investigating whether the gas leak caused the explosion.