Police also seized firearms-a pistol, a revolver and three live ammunitions and a motorcycle from their possession, a police officer said.
The accused persons identified as Jhumura Biswal of Bhatapada village, Uma Shankar Bisoi of Balipada and S Kalia alias Santosh Reddy of Kabisuryanagar were arrested from Haradakhandi area in Berhampur.
Other three members in the gang allegedly involved in at least six petrol pump dacoity cases in Ganjam and Kandhamal district, however remained absconding, said sub divisional police officer (SDPO) Berhampur P K Patnaik.
Search was intensified to nab the other three gang members involved in the crimes, added Mishra.
The gang used to terrorise employees of the petrol pump by firing in the air before executing the crime. In some cases, they also injured the employee by opening fire and then decamped with cash, police said.