Boko Haram extremists on Tuesday killed 10 people and wounded 21 with mortar shells in Nigeria's volatile city of Maiduguri.
The insurgents fired two volleys of explosives on the city, hitting the densely populated Adamkolo and Gwange neighbourhoods, residents and militias told AFP.
"We have six dead in Adamkolo and four others in Gwange from the mortar explosions," militia leader Babakura Kolo said.
"The explosives were fired by Boko Haram terrorists from Kaleri on the outskirts of the city."
At least 16 people were injured in Gwange and five in Adamkolo, said another militiaman, Umar Ari.
Witness Samaila Ibrahim said the extremists crossed the ditch fortification around Maiduguri into Kaleri, sending residents rushing for safety with sporadic shooting.
"Luckily they didn't hit anyone," Mr Ibrahim said.
He said the militants came through Boboshe village, a known Boko Haram enclave.
Boko Haram has repeatedly made incursions into Maiduguri, using heavy guns, rocket-propelled grenades and suicide bombers.
The attacks aimed at overrunning the regional capital have usually been foiled in fierce gun battles with troops.
In February last year, Boko Haram fired volleys of rocket-propelled grenades into the city, injuring several people.
Since it began in 2009, the conflict has killed 36,000 people and displaced about two million from their homes in north-east Nigeria, sparking a humanitarian crisis in the region.
The violence has spread to neighbouring Niger, Chad and Cameroon, prompting a regional military coalition to fight the insurgents.