Arms were seized from the vehicle deserted by the three persons before they entered the residential society, Senior Superintendent of Police Nitin Tiwari said.
The area has been cordoned off and search operation launched to arrest the trio, he said.
SP City Shiv Shankar Yadav said the three persons were spotted in the Govindpuram and on being challenged they opened fire at the police party and ran inside a housing society in the area.
According to Yadav, the car has a sticker of the housing society.
The flat belongs to a woman, who shifted there today, he said, adding previously few youths stayed in the flat as tenants.
"The matter is being probed," he added.