Voters and electoral officials fled in different directions when explosion rocked the polling unit at Umuola Hall, Ward 8, Ogbor Hill, Aba North Local Government Area of Abia State, on Saturday.
The Independent National Electoral Commission (INEC) is currently conducting a bye-election in Aba North/Aba South Federal Constituency.
Ossy Prestige, the lawmaker who represented the constituency at the House of Representatives, died on February 6 and his seat was declared vacant.
Ahead of the bye-election, top politicians in the area had engaged in a heated argument. They had accused one another of plotting to instigate violence during the exercise.
The election was going on smoothly at the affected polling unit until a substance suspected to be a bomb went off.
It was gathered that no life was lost in the incident but some electoral materials were reportedly affected.
It is not clear if a bomb was planted at the polling unit to scare away voters.
Security agents later stormed the scene to restore order.