The incident took place when the truck of a courier company rammed into the pandal where the reception ceremony was being held last night, Superintendent of Police Mohit Gupta said.
The injured were taken out from the pandal with the help of a crane and taken to NTPC hospital at Unchahar, the SP said, adding that they were later referred to the district hospital.
The deceased have been identified as Nidhi Modanwal, Mohd Shareef, Manoj Gupta, Jitendra Kumar and Vinayak, police said.