Buhari met with his top security chiefs last week and again on Tuesday to discuss the country’s violence.
“We shall continue to discharge our constitutional responsibilities professionally, especially in protecting the country’s democracy, defence of the territorial integrity of the country as well as protection of lives and properties of citizens,” the military statement said.
The army expressed the hope that the nation’s “current security challenges are not insurmountable.”
Nigeria returned to democracy in 1999 after almost 16 years of military rule.
Buhari, a former army commander and military ruler in the 1980s, was first elected in 2015 and re-elected four years later on a pledge to end the Boko Haram insurgency in the northeast.
Rather than abate, the Islamist rebellion has stubbornly persisted with a Boko Haram splinter faction, Islamic State West Africa Province (ISWAP), becoming the dominant jihadist force.
Since 2009 when it began, the jihadist uprising has killed 36,000 people and forced over two million others to flee their homes in Nigeria’s northeast alone.
The violence has also spread to neighbouring Chad, Niger and Cameroon, prompting a regional military coalition to fight the insurgents.