However, no one was injured in the firing, police said. The two robbers were arrested after they fell off their motorbike near Lahori Gate.
The duo, identified as Pradeep (22) of Baghpat and Satpal (32) of Aligarh, were part of a five-member gang, police said.
The gang members raided the office at Vishnu Bazar around 3 PM and looted Rs 3.5 lakh in cash after pointing pistols at its employees. They also thrashed a private security guard deployed outside the office.
Two policemen deployed in the area noticed the duo and tried to stop them who by then had managed to kick-start the two-wheeler. The policemen then chased the motorcycle and arrested the duo.
Around Rs 2 lakh of the robbed cash has been recovered from them, along with arms and ammunition. The accused have been charged with dacoity and attempt to murder among others.
Police said Pradeep was involved in at least 11 cases of robberies. A hunt is on for the remaining accused, they added.