Sounds of gunshot rocked unit 17, ward 5, Osogbo local government area of Osun state around 12pm on Thursday as voters and electoral observers scuttled to safety.
Suspected thugs had invaded the unit to disrupt the exercise but the security personnel on ground fired shots into the air to prevent them.
The exercise has been fraught with irregularities in at least four of the seven polling units where it is taking place.
Meanwhile, Ademola Adeleke, candidate of the Peoples Democratic Party (PDP) in the election, has described the rerun election as a coup.
“What is happening in Osun State now is not an election. What we have is a coup. That is what we are witnessing now,” he told PUNCH.
“Our supporters are being harassed and are not allowed to vote at all. Let the whole world know that this is not the democracy.”