Miscreants hurled a petrol bomb at the Kilpauk branch of Andhra Bank past midnight on Thursday.
The attack is suspected to be a response to the death of 20 men from Tamil Nadu in an encounter by the Andhra Pradesh police in Chittoor on April 7.
Police said the attack took place minutes past midnight when two men, who had reportedly arrived in a motorcycle, hurled a bottle containing petrol with its wick ablaze.
The bank branch on New Avadi Road also has an ATM facility in the building.
Govindaraj, the security guard on duty on the premises, rushed in after hearing the loud noise and noticing the fire in front of the bank, but could not spot the attackers. The guard immediately alerted his superiors, who informed the police.
A police patrol team reached the spot and seized the fragments of the petrol bomb for expert examination.
TP Chatram police have registered a case and are examining footage from two CCTV cameras installed outside the bank branch.
The city witnessed a spate of attacks on supermarkets and other commercial establishments soon after the killing of the 20 men.
Their deaths had evoked angry reactions from several political parties and other organisations.
