What you need to know:
- Bomber was on a bicycle when he approached a group.
- Muna area of Maiduguri is home to a vast camp for people displaced by the conflict.
- The military and government maintain the Islamist militants are a spent force.
A suicide bomber on a bicycle killed three people late on Monday when he detonated his explosives on the outskirts of the northeast Nigerian city of Maiduguri, civilian militia said.
Eighteen people were injured in the attack, which happened in the Muna Dalti area of the city, said Musa Ari, a civilian helping with security against Boko Haram.
"The bomber attacked at 8.20pm in the midst of a group of residents hanging out, killing three and wounding 18," he said. "There is no doubt this is the work of Boko Haram terrorists."
Another militia leader, Ibrahim Liman, gave the same toll and said the bomber detonated the explosives as he passed the group.
The Muna area of Maiduguri, which is home to a vast camp for people displaced by the conflict, has been repeatedly hit by suicide attacks blamed on Boko Haram.
Previous targets include the camp itself, military and civilian militia checkpoints, and a bus station.
Boko Haram has increasingly used mostly female bombers against civilian soft targets, particularly mosques, markets and other gatherings, as part of its insurgency.
On Sunday, three female suicide bombers died in a botched attack in Konduga town, 38 kilometres from Maiduguri, the militia said.
Liman said the bombers' veils became entangled in barbed wire security fence erected by vigilantes to fend off Boko Haram suicide attackers.
"The bombers blew themselves up to avoid capture and injured one person nearby," he added.
Nigeria's military and government maintain the Islamist militant are a spent force, after a sustained counter-insurgency that began in early 2015.
But while the jihadists no longer hold the territory they once did in the northeast, there are indications they may be stronger than the authorities claim.
On February 19, heavily armed fighters kidnapped 110 schoolgirls from the town of Dapchi, in Yobe state, while last Friday, militants attacked the town of Rann in Borno.
Eight soldiers and three aid workers were killed, forcing the suspension of humanitarian operations in the remote town for a week.