A bus driver detonated the bomb at a military checkpoint near Maiduguri in Nigeria's northeast, killing at least one civilian and wounding three others, sources from Nigeria's military and the civilian joint task force (JTF) said on Monday. The bomb went off at around noon, they said.

"There have been casualties but we're still working to confirm the numbers," said Babakura Kolo, who is a member of the JTF, a vigilante team assisting the military against Boko Haram.

No group immediately came forward to claim responsibility for the bomb blast, but the attack bore the hallmarks of Islamist militant group Boko Haram. Maiduguri is the birthplace of the terror sect.

Latest in a string of attacks

Attacks have been on the rise ever since President Muhammadu Buhari took office at the end of May.

On Saturday, two suicide bombers tried to attack a crowded bus station, but were foiled by heavy security. Shortly after, a man wearing a full-face veil killed 15 people at a busy market in Chad's capital N'Djamena - Chad is Nigeria's ally in the fight against Boko Haram.

Buhari, who has vowed to crush the terror group, sacked his chiefs of the army, navy and air force on Monday. The move was widely seen as a measure to make cracking down on Boko Haram a priority. A spokesperson for Buhari said the president would soon announce their replacements.

sst/ tj (AFP, Reuters)