The girls, who were "under 15", attacked the central market of the regional capital Maroua as well as the adjoining Hausa neighbourhood, regional governor Midjiyawa Bakari said.
Bakari said several people were killed and at least 22 injured, without giving a precise toll.
A source close to local authorities confirmed the attack, saying "two girls who were begging blew themselves up" at around 3 pm. The source said around 10 people had been killed.
The attack is the second of its kind in Cameroon in the past 10 days.
On July 12, two female suicide bombers blew themselves up in Fotokol, on the border with Nigeria, killing 10 civilians and a soldier from neighbouring Chad.
Over the past two years Boko Haram has carried out several raids and abductions in northern Cameroon but the country, which is engaged in a regional fightback against the jihadists, had previously been spared from suicide attacks.