Five people were killed when a bomb exploded at the office of the country`s Independent National Electoral Commission (INEC) located in the northern city of Suleja, near the country`s capital yesterday, officials said.
"There was explosion with some casualties but the injured have been taken to a nearby hospital for treatment," Yushua Shuaib, spokesman for Nigeria`s National Emergency Management Agency (NEMA) told PTI.
He, however, refused to give the actual figure even as the police and INEC officials declined comment but sources told PTI that number of dead were five whereas ten others were injured.
Bomb attacks have been witnessed during the campaigns and a prominent militia group, Movement for the Emancipation of the Niger Delta (MEND) had threatened to disrupt the electoral process but later withdrew its warning.
MEND, which claims to be fighting for better resource control, is based in the oil rich Niger Delta but in the north another group -- Boko Haram has been killing politicians after issuing its own threat earlier.
Four persons, including three electoral officers and a party chief, were killed in northern state of Borno when gunmen opened fire on them while they were preparing to give the voting materials to the polling officials, they said.
Police confirmed the party official killed was associated with the ruling Peoples Democratic Party (PDP).
Election to the country`s senate and lower house of representatives was scheduled for April 2 but had to be postponed till today due to logistic issues.
It is the first in series of elections that would see the oil rich African country elect a president and 36 state governors.
Boko Haram is an Islamic sect that wants to install Sharia rule in the country and on the process preaches against Western education. Brono state is has been hit by repeated killings and attacks by Boko Haram.
The country has tightened its internal security by closing its land borders through the period of the elections which is the fourth since return to democracy in 1999.