Two weeks to the March 28 elections, some suspects have been caught with over 500 Permanent Voter Cards at Orita Sekoni area of Ogbomoso, Oyo State.
The suspects were said to have been arrested in connection with the incident while the driver of the car ran away.
The police reportedly fired shots into the air to stop the clash that greeted the incident.
Eye witnesses said irate youths could have lynched the suspects if the police had not responded promptly.
A source said the cards were sighted in the car after some residents, who acted on a tip-off, forced the car to stop.
The suspects were said to be known supporters of one of the opposition parties in the state.
Several calls made to Oyo State Police Public Relations Officer, DSP Adekunle Ajisebutu, for comments on the incident were not picked.