The incident took place when three persons, who had covered their faces, stopped a security van and opened-fire, injuring three and fled away with about Rs 20 lakh, they said.
The injured were rushed to a hospital where their condition was stated to be stable.
Later, senior officials reached the spot and took stock of the situation.
No arrests have so far been made in this connection. Police is going through CCTV footage of the area to solve the case.