The burglars had gained entry into Canara Bank's Senthurai Main Road branch by breaking open the ventilator of the toilet.
They damaged the Closed Circuit TV cameras and then tried to deactivate the alarm system of the bank.
As the bell rang with high decibel noise for a long time, people in the neighbourhood rushed to the bank, forcing the burglars to retreat and escape.
Police who rushed to the spot found the ventilator at the toilet broken and the rear door open.