Nigeria’s President Muhammadu Buhari has sacked the army, navy and air force chiefs, his spokesman has told the BBC.
Mr Buhari is expected to announce their replacements soon.
This move does not come as a surprise, as the president has repeatedly criticised the military’s inability to defeat Islamist militants Boko Haram.
After losing most of their territory earlier this year, they have recently launched a series of deadly guerrilla attacks, killing more than 250 people.
The new military chiefs will be expected to work closely with neighbours Chad, Cameroon and Niger as the countries join forces to tackle Boko Haram.
The group has also stepped up attacks on these countries.
At least 12 civilians were killed in Cameroon in a suspected Boko Haram suicide attack on Sunday evening, a military source told the BBC.
Two soldiers also died along with the two bombers when they blew themselves up in Fotokol, near the border with Nigeria.
Chad will be the headquarters of an expanded Nigeria-led regional force of around 7,500 troops.
Its formation has gained momentum since President Buhari took office in May.
On Saturday morning, 15 people died in the main market in Chad’s capital, N’Djamena when a man dressed in a burka blew himself up. Boko Haram claimed responsibility for the attack.