Locals and street vendors said the explosion came from a passing motorised rickshaw and the Borno State Secretariat may not have been the intended target.
The Boko Haram Islamist group was founded in Maiduguri in 2002 and the city has been repeatedly attacked since the insurgency turned violent in 2009. But a relative calm has returned to the city in recent months as a military counter-insurgency makes apparent gains against rebel strongholds across the northeast.
The last successful attack in Maiduguri was a double suicide bombing by two women at a mosque in Molai, on the outskirts of the city, in March in which 22 people were killed and 35 injured.
There was no immediate claim of responsibility for the latest blast or indication of its cause. “It’s not clear how many people there were in the tricycle (rickshaw) but evidently the explosion was accidental,” said one man, who asked to remain anonymous.
“The tricycle was heading to another destination. The explosives went off prematurely.”
A vegetable trader outside the government offices added: “I was attending to my customers when I heard a loud explosion and instantly I knew it was an attack. “I took cover. Moments later I realised the explosion was from a tricycle which blew up just metres away from the gate of the secretariat.
“It went up in flames and there was nothing but charred remains of the tricycle.”