A major blast was reported on Sunday in a firecrackers unit in Andhra Pradesh's Visakhapatnam district when 10 to 15 people were working there, police said.
The number of casualties were not immediately known, police said.
The accident occurred in Gokulapadu village of S. Rayavaram mandal, about 100 km from coastal city of Visakhapatnam.
Police said loud explosions were heard and fire engulfed the building. Fire tenders from nearby villages rushed to the scene.
The exact number of victims will be known after clearing the debris. According to eye-witnesses, 10 to 15 people were working at the time of the disaster.
The cause of the explosion and fire is under investigations, police said.