A blast ripped through a car park outside a stadium where Nigeria's President Goodluck Jonathan had addressed a re-election campaign rally on Monday, minutes after he left, witnesses said.
Mohammed Bolari, who was at the rally in the northeastern city of Gombe, said the explosion happened at 3:10 pm (1410 GMT), just three minutes after Jonathan's departure.
A local reporter added: "The president had just passed the parking lot and we were trailing behind his convoy when the explosion happened... just 100 metres (yards) from the bus we were driving in."
GMT 18:40 2017 Monday ,24 AprilHollande 'will vote Macron', calls Le Pen 'risk' for France
GMT 09:35 2017 Monday ,24 AprilGerman DAX stock market index hits new all-time high
GMT 08:13 2017 Monday ,24 AprilFirst large-scale malaria vaccine trials for Africa
GMT 08:11 2017 Monday ,24 AprilPentagon chief Mattis makes unannounced Afghan visit
GMT 07:29 2017 Monday ,24 AprilEuropean stocks surge at open on French vote result
GMT 07:27 2017 Monday ,24 AprilAfghan defence minister, army chief resign after Taliban attack
GMT 06:12 2017 Monday ,24 AprilPhilips posts first quarter jump in profits
GMT 06:10 2017 Monday ,24 AprilIn call with Trump, Xi urges 'restraint' on N. Korea