Updated at 3:30 p.m. Tuesday: The St. Louis Fire Department determined Monday's fire at Goody Goody Diner started in electrical equipment in the refreshment prep area of the kitchen and was accidental.

ST. LOUIS • Firefighters battled a kitchen blaze Monday night at the fabled Goody Goody Diner on Natural Bridge Avenue near Goodfellow Boulevard in north St. Louis.

The popular diner was closed when it caught fire and no injuries were reported.

Firefighters responded at about 9:40 p.m. when heavy smoke poured out of the restaurant. They had to cut open the metal doors to get into the building, according to St. Louis Fire Department Capt. Leon Whitener.

No flames were visible from the outside when firefighters arrived and the fire seemed to have mostly burned itself out. With the building's insulation and tight spaces, there wasn't a lot of oxygen for the fire to feed on, Whitener said.

The fire seemed to have started in the kitchen although an investigation is underway. The fire also caused smoke damage to the dining area, Whitener said.

"Unfortunately I don't think they'll be open anytime soon," Whitener said.