A number of people have been killed in a suspected bomb blast at a Nigerian election office in Suleja, on the northwestern edge of the capital Abuja.
There are also reports that four others were shot dead at a police station in Shani in Borno in the north east, as they prepared to distribute election leaflets.
The violence is a futher blow to hopes of an orderly election in Nigeria, already a week late because of poor organisation.
Human Rights watch estimate that as may as 85 people have been killed in political violence linked to the election campaign.
Boko Haram, a radical Islamist sect is being blamed for the upsurge in violence in the north east.
Yet, some analysts believe their name is being used as a front to cover UP general political intimidation.