Replacements would be announced later on Monday, the presidency spokesman told Reuters.
Since his inauguration in May, Buhari has moved Nigeria’s defence command centre to Maiduguri, the birthplace of the jihadi sect, and is setting up the headquarters for a multi-national joint taskforce in Chad’s capital N’Djamena.
In June, Amnesty International accused Nigeria’s military of systemic human rights abuses and the deaths of 8,000 prisoners and called for an investigation into many top military officials including the army and air force chiefs.
Former President Goodluck Jonathan was heavily criticised for his inability to deal with the six-year insurgency in the northeast of Africa’s biggest oil producer which has killed thousands and displaced 1.5 million people.
Army morale hit an all time low under Jonathan and it was not until the start of 2015 that the militants were finally pushed out of most areas with the help of foreign mercenaries, troops from neighbouring countries and new equipment.
But Nigerians saw Jonathan’s victories as too little to late.
The outgoing officials are: Chief of Defence Staff, Air Marshall Alex Badeh; the Chief of Army Staff, Major General Kenneth Minimah; the Chief of Naval Staff, Rear Admiral Usman Jibrin and the Chief of Air Staff, Air Vice Marshall Adesola Amosu, the spokesman said.