Five people sustained injuries when a bomb exploded outside an election office of Pakistan Peoples Party (PPP) in Quetta on Friday.
According to initial reports, the blast occurred near the Western Bypass.
Many vehicles were reportedly damaged in the attack.
Police and rescue officials reached the area.
A bomb disposal squad (BDS) was also summoned.
Political parties have been under attack since the poll date was announced and around 100 people have lost their lives due to election violence.