A policeman sustained gunshot wounds in Sector E-11 of the federal capital, 24NewsHD TV channel reported on Tuesday.
A Dolphin squad flagged down a suspicious vehicle but the riders fired shots at the lawmen, leaving one of them injured.
The injured cop, identified as Tanveer, was shifted to PIMS in a critical condition. He was shot in the rib and leg.
The shooters fled from the scene. Local police have launched a hunt for the fugitives after cordoning off the area.