Authorities are investigating a fire at Stefano's Brooklyn Pizza in Harlingen, Monday morning. 

According to Harlingen fire Chief Rafael Balderas, firefighters responded to the restaurant at about 5 a.m. Monday after receiving a call for an activated alarm. 

When crews arrived, they noticed smoke inside and broke through one of the doors. 

"We did find a big fire inside the building and so we started fighting the fire and then it got too intense that we got into defensive mode, which is what we're doing right now," Balderas said at the scene. 

The owner of the restaurant tells Channel 5 News that the restaurant was more than just the food, but also the environment that the staff created for his guests. 

The cause of the fire remains under investigation. No injures were reported.