NEPTUNE BEACH, Fla. -

The Jacksonville Fire and Rescue Department is working to find out the cause of a fire at a Neptune Beach restaurant, early Thursday morning.

Around 3:51 a.m. JFRD responded to a fire at Ray's Pizza  on 240 3rd Street, formerly known as Mario's Restaurant and Pizzeria.

Several units responded and extinguished the fire.

JFRD said no one was injured or inside the building during the fire.

Neptune Beach police closed 3rd Street between Atlantic Boulevard and Orange Street for a little over an hour during the fire fight.

We do not yet know where the fire started or what caused it, but JFRD suspects the fire had something to do with the window a/c unit.

Most of the damage is at the front interior of the restaurant.

We have a crew on scene gathering details on the fire and we will give you updates on News4Jax and on The Morning Show.