MAIDUGURI, Nigeria (AFP) - A female suicide bomber on Tuesday blew herself up near a military checkpoint in restive Nigeria's northeastern Borno state, killing four people, witnesses said.
"The woman... alighted near a military check point in Sabon Gari where she blew herself up and killed four other people," witness Maikaho Abdu told AFP.
He said the attack happened at Sabon Gari village, along Gombe road, some 110km from Maiduguri, the state capital.
Abdu, who is a commercial driver, said two civilian vigilantes assisting the military in the fight against Boko Haram Islamists and two other people were killed in the incident.
Vigilante Yusuf Ardo said the blast happened around 10.30am in the morning.
"The woman strapped herself with the explosives and alighted from the vehicle, some metres away from the checkpoint as if she had reached her destination," he said.
A senior military officer, who did not want to be identified, also confirmed the attack.
"The terrorist killed herself and four others in the attack," the military officer told AFP, without giving further details.
There was no immediate claim of responsibility for the attack, but Boko Haram Islamists have carried out a series of deadly assaults, including through female suicide bombers, in their six-year-old insurgency in the volatile north-east.
Borno state has been repeatedly targeted in such attacks.
The hardline Islamist group has stepped up attacks since May 29 when President Mohammadu Buhari came to power.
With the latest attack, more than 550 people have been killed since Buhari's inauguration, according to a tally by AFP.
The president has vowed to crush the rebellion with the help of a 8,700-strong regional military force that will deploy at the end of the month.