AFP/ Kano

Nigerian soldiers shot dead a suspected suicide bomber outside a military base in the northeast on Sunday, detonating explosives concealed in her handbag, a civilian vigilante and a military source told AFP.

The target was thought to be the Maimalari army barracks -- the main military base in Maiduguri, which has been hit repeatedly in recent months by Boko Haram.

"Soldiers at Maimalari army barracks this morning (Sunday) foiled a suicide attack by a female bomber," said Babakura Kolo, from the civilian volunteer force assisting troops against the rebels.

The woman approached the barracks around 7:00 am (0600 GMT) and headed towards the gates, he said. Military guards at the gates shouted at her to stop for security checks but she ignored them and continued walking towards the gates, he added.

"She continued walking with her handbag slung on her shoulder, despite repeated shouts from the soldiers asking her stop.

"One of the soldiers opened fire on the woman and the handbag exploded, blowing the woman to pieces."

There were no other casualties in the explosion, which one military officer in the city described as an "attempted suicide attack by Boko Haram terrorists".

Boko Haram has intensified its use of multiple suicide bombers to inflict maximum casualties, with secondary explosions detonated as people rush to help victims of the initial blast.

At least 34 people were killed in a wave of attacks on Thursday night and Friday morning on the outskirts of Maiduguri, while last month 117 died in explosions in the Ajilari Cross area of the Borno state capital.

Of the six suicide attacks in Nigeria this month, four have been in Maiduguri, killing at least 48 and injuring 99.

The military source, who requested anonymity as he is not authorised to talk to the media, said the use of human bombs was a sign of the group's desperation and frustration at the fight-back by troops.

"They are looking for every opportunity to hit back, which is why they have resorted to soft-target attacks on mosques and markets and such attacks on a military base is intended to show the terrorists are still strong," the officer added.