A child bomber has killed up to six people outside a bus station in the heartland of the Boko Haram Islamist insurgency in northeastern Nigeria.
Witnesses reported seeing a "young girl" trying to get into the station in the Yobe state capital Damaturu around 7am (local time) and refusing to be searched by security guards at the gate before blowing herself up.
"A private taxi ... drove out of the park. As soon as the car came close, she detonated the explosive. Six people in the car were killed. She was also killed," bystander Sani Dankamasho told AFP.
Bloomberg News put the girl's age at about 12, citing a bus driver who witnessed the blast.
The attack came just hours after United Nations chief Ban Ki-moon wrapped up two-day a visit to Africa's largest economy during which he hailed its "greater stability and peace" under its new leader as he commemorated a deadly 2011 attack on the global body by Boko Haram militants.
No group immediately claimed responsibility for Tuesday's bombing – which also wounded up to 28 people – but it bore the hallmarks of Boko Haram, which has in recent weeks used young women to carry out bloody suicide attacks in the restive northeast.
A journalist working for a private newspaper in Damaturu who arrived at the scene soon after the blast confirmed the death toll.
Boko Haram has stepped up attacks in Yobe and two other states in its northeastern bastion since President Muhammadu Buhari came to power on May 29 amid a wave of optimism that he could tackle the worsening security situation.