Photo: The Canadian Press

California firefighters who spent 20 minutes performing mouth-to-snout resuscitation on a dog they rescued from a burning apartment are being hailed as heroes.

The dog's owner, 35-year-old Crystal Lamirande, had just returned to her Santa Monica apartment Tuesday when a neighbour yelled there was a fire.

Lamirande frantically tried to save her dog, a 10-year-old Bichon Frise/Shih Tzu named Nalu, but the smoke was too thick for her to go inside, she said Thursday.

Moments later firefighters arrived and Lamirande told them her dog was trapped inside.

That's when firefighter Andrew Klein sprang into action, getting on all fours to search the apartment for Nalu as another firefighter sprayed water to keep the flames at bay. Klein found the unconscious dog a few feet from the fire in a bedroom.

"He was totally lifeless," Klein said. "I picked him up and ran out of the apartment because time is key, especially with a small dog ... Failure was not an option."

As Lamirande knelt nearby crying, Klein and his crew spent the next 20 minutes working on reviving the dog using oxygen, CPR and what's known as mouth-to-snout resuscitation.

Video taken by a passerby and posted on Facebook shows Klein and another firefighter patting Nalu's belly as he starts breathing again with the help of oxygen.