MAIDUGURI (Reuters) - A female suicide bomber has killed two people and injured three others at a checkpoint in the northeastern Nigerian city of Maiduguri, military sources said on Thursday.

The explosion, at around 1615 GMT, struck near army barracks and follows a spate of bombings in the city by militant Islamist group Boko Haram that has killed around 80 people in the last few days.

The female bomber, who wore a veil and concealed explosives on her body, detonated the bomb beside a checkpoint on the outskirts of the city, said military sources.

"Two people died and three were injured," Borno Police Commissioner Aderemi Opadokun told Reuters.

Boko Haram has waged a six-year insurgency in the northeast of Africa's most populous country in a bid to carve out an Islamic caliphate.

At the start of the year it controlled a swathe of territory around the size of Belgium, but the military says the group has been pushed back to the Sambisa forest in recent weeks - which Boko Haram denied in a video aired on social media on Tuesday.

New President Muhammadu Buhari, who visited his counterparts in Niger and Chad on Wednesday and Thursday to discuss the group, has vowed to defeat the militant Islamists.