K Sandwiches at 7604 Linda Vista Road went up in flames around 9 p.m. Tuesday, according to the San Diego Fire-Rescue Department.
Firefighters initially went inside the burning single-story restaurant but were ordered out after officials decided that conditions were too dangerous, said SDFRD Capt. Joseph Amador. They then fought the blaze from the exterior.
Firefighters spotted a drone flying in the area. Fire officials asked its operator via Twitter to cease flying near the restaurant because firefighter atop ladders "don't need the unsafe distraction."
Amador said most of the fire was knocked down in about an hour, and firefighters would keep watch overnight to guard against flareups. They were also looking into whether a faulty stove caused the fire.
The restaurant's 88-year-old owner was hospitalized for stress related issues after the fire broke out, but she was out of the hospital and doing better Wednesday morning, family members told FOX 5.
K Sandwiches is known for its Vietnamese-style banh mi sandwiches. The family-owned business is not a franchise. Family members told FOX 5 that they hope to rebuild the restaurant.