An apparent car bomb killed at least nine people Thursday on the outskirts of the Nigerian capital Abuja.
The blast in the suburb of Nyanya was near the site of an April 14 bombing at a bus station that killed at least 75 people.
The Islamic extremist group Boko Haram claimed responsibility for the April blast and promised more attacks.
Nigeria is planning to host the World Economic Forum on Africa next week. President Goodluck Jonathan has promised extraordinary security measures for the meeting.
He said Nigeria will triumph over what he calls the evil that wants to debase humanity.
Boko Haram has killed thousands in a five-year insurgency to set up a hardline Muslim state in northern Nigeria.
Militants from the group are suspected in last week's kidnapping of more 250 schoolgirls in northern Nigeria. Some reports say the militants are forcing the girl into marriage.