At least three robbers tried to break into a bank at Kaveli village under Zaheerabad Police station limits at about 1.30 am, but fled when the internal alarm went off.
Police Sub-Inspector Venkatesh, who rushed to the spot after being alerted, chased them.
"The accused fired at least five rounds and two of them hit him," a senior police officer told PTI over phone from Sangareddy.
The PSI was operated upon at a hospital in Hyderabad and his condition was now stable, the officer added.