Police in Nigeria say casualty totals have risen to three dead, 14 wounded from Sunday's bomb blasts in the northeastern city of Maiduguri.
Authorities are blaming the radical Islamic sect Boko Haram for the attacks, which occurred ahead of nationwide gubernatorial elections Tuesday.
A total of three bomb blasts went off at a hotel and a motor park. Authorities say all the casualties resulted from the hotel attack.
Police also blame Boko Haram for an explosion in Maiduguri early Monday that injured one policeman. A local journalist told VOA that the bomb apparently was intended for a police checkpoint but was either thrown off-target or landed in a ditch, reducing its impact.
Police suggest the Boko Haram militants trying to intimidate voters before the polls open Tuesday. The group's name means "western education is sinful."
Elections are scheduled to be held in most of Nigeria's 36 states. Voting in northern Kaduna and Bauchi was delayed for two days because of security concerns.
Riots broke out in the predominantly Muslim north last week after election officials announced that President Goodluck Jonathan, a Christian from the south, had won the presidential ballot. The violence killed at least 500 people.
Nigeria, Africa's most populous country, is divided about evenly between Muslims, who mostly live in the north, and Christians, most of whom live in the south.
Some information for this report was provided by AP, AFP and Reuters.