A popular Vietnamese sandwich shop in Linda Vista is a total loss after it erupted in flames Tuesday night, San Diego Fire-Rescue officials said, causing the owner to suffer a medical emergency.

A cooking fire started in the oven of K Sandwiches at 7604 Linda Vista Road just before 9 p.m. The flames were discovered by the owner and workers as they were getting ready to close up shop.

When firefighters arrived, they found heavy smoke and flames pouring from the business. Drones soon started flying above, and while they did not interfere in the firefighting efforts, officials were concerned about them. The SDFD tweeted a request for their operators to stop.

Officials say everyone inside made it out safely, but the owner suffered an unknown medical emergency after seeing what happened to his business.

"That's kind of very tragic, seeing a place like this — a very beautiful, busy place — going up in smoke like that, it's tragic," said De Le, who visited the restaurant only eight hours ago.

Firefighters say it was difficult to reach the center of the fire as it burned through the roof, which meant the structure had been compromised, according to SDFD Deputy Chief of Operations Steve Ricci. Crews were then forced to take a defensive approach.

"It was a stubborn fire. I've got over 30 years with San Diego Fire-Rescue, and I haven't seen a fire like this in a long time," said Ricci.

The counter-service restaurant, which specializes Bahn Mi sandwiches, breads and other Vietnamese food, suffered about $1.5 million in damage.

Ricci said crews will be on the scene for another two to three hours.