Previously, the agency reported that the explosion had almost destroyed the entire building. None of the groups operating in the region have claimed responsibility for the attack.
"A suicide bomber with a homemade bomb blew himself up in a mosque, 26 people were confirmed dead, and another 28 were injured," AFP reports, citing Borno's state police commissioner.
Suicide bomber kills himself, 16 others outside mosque in Maiduguri, Nigeria, hours after grenade attack: http://t.co/2UNC4zWVcV— The Associated Press (@AP) May 30, 2015
None of the terrorist groups operating in the region have claimed responsibility for the attack.
On the night of Friday to Saturday, Nigerian rebels have launched an assault in the city of Maiduguri and killed at least 11 people, but the Nigerian army managed to negate attacks.
The attack and the Boko Haram assault that night occurred only hours after the swearing in of the new president, Muhammadu Buhari, who has made the fight against the northern militants a priority.
Buhari has also announced plans to create a new command center in Maiduguri, instead of Abuja, in order to fight Boko Haram more effectively.