The bomber blew herself up among Saturday night revellers in the popular bar, injuring at least 79 others, state TV reported. An earlier toll put the number of dead at 14.
There was no immediate claim of responsibility for the attack, but the north of the country has been repeatedly targeted by Nigeria-based Boko Haram extremists.
” A girl of around 12 blew herself up between two takeaway sales points. Security forces have sealed off the area and have made several arrests,” the state TV channel said.
The atrocity came a day after Boko Haram were also blamed for a wave of a attacks on villages across the border in northeastern Nigeria that left at least 25 dead and forced hundreds more to flee their burning homes.
Cameroon’s army has joined the regional military offensive against the extremists after suffering repeated deadly raids into its territory.
Third bomb attack by girls
Maroua — the commercial hub of the extreme north of Cameroon close to the Nigerian and Chadian borders — was already reeling after 13 people were killed in twin suicide bombings on Wednesday in a central market and in a nearby neighbourhood by two teenage girls.
A police officer at the scene of the bar bombing said he had counted “12 bodies” shortly after the attack but the toll later rose.
A resident told of “a loud explosion”, saying they had learnt there was an attack at the Boucan bar, a large and popular nightspot.
Maroua has been under heavy security for months as the threat from Boko Haram has grown, with motorbikes — which the insurgents often use to stage their raids — banned from the streets after dark.
Boko Haram has recently stepped up its attacks in the restive Lake Chad region despite a major regional offensive against the extremists.
Over the past two years the group has carried out several cross-border raids and abductions in northern Cameroon but the country, which is playing a key role in a regional fightback against the jihadists, had previously been spared suicide attacks.
Last week, Cameroon extended a ban on full Islamic veils in parts of the country as it seeks to curb the threat from female suicide bombers.
The full veil was already banned in the northern and western regions of the country.
Muslims make up around one quarter of the population. It is now also forbidden in the east.
A new, five-nation force — from Nigeria, Niger, Chad, Cameroon and Benin — is due to deploy by July 30 to take on the militants, whose six-year insurgency has left at least 15,000 dead. – AFP