Old Lyme ― The town’s fire marshal is investigating the cause of a fire early Monday that caused significant damage to the Sapore Pizzeria at 163 Boston Post Road.

The Old Lyme Fire Department responded to the popular eatery at 4:20 a.m. to find a fire in the kitchen area, Old Lyme/Lyme Fire Marshal David Roberge said. The fire was contained to the kitchen of the restaurant but caused extensive damage.

The restaurant was not occupied at the time of the fire and no injuries were reported. Roberge said the cause of the fire remains under investigation.

The restaurant is expected to be temporarily closed and efforts are under way to board up and secure the premise. Health district officials are expected to determine if some of the food stored at the restaurant is salvageable.

Old Lyme firefighters were joined by firefighters from the Old Lyme, East Lyme, Old Saybrook, Clinton, Essex and Lyme fire departments.