At least 10 people, including the attacker, were killed Wednesday in a suicide bombing at a mosque in the northeastern town of Gamboru, Nigerian police said.

The assailant, suspected of being affiliated with the Boko Haram terror organization, detonated an explosive vest inside the mosque as worshippers were gathered for prayers.

Gamboru lies in Borno State, near the border with Cameroon.

An investigation is under way, a spokesperson for the state police told EFE from Maiduguri, Borno's capital.

Though President Muhammadu Buhari insists that Boko Haram has been defeated, the group's fighters continue to carry out attacks on mosques, schools, markets and refugee camps in the northeastern part of the African country.

Nigeria has seen an increase in the number of suicide attacks in recent months, despite a vigorous counter-terrorism campaign by security forces.

Boko Haram has killed more than 20,000 people and forced about 1.9 million to leave their homes since 2009, according to United Nations figures.