Obasanjo in the letter released by his media aide, Kehinde Akinyemi, had expressed worry over high level of insecurity in the country.
He called on the President to take decisive action to prevent the situation from escalating into a full-blown crisis.
According to the letter: “I am very much worried and afraid that we are on the precipice and dangerously reaching a tipping point where it may no longer be possible to hold danger at bay.
“Without being immodest, as a Nigerian who still bears the scar of the Nigerian civil war on my body and with a son who bears the scar of fighting Boko Haram on his body, you can understand, I hope, why I am so concerned.”
Reacting, the ACF said it was still studying the letter and will speak on it soon.
“Arewa Consultative Forum (ACF) is studying Chief Olusegun Obasanjo’s open letter to President Muhammadu Buhari and will make it’s position known soon,” the National Publicity Secretary, Muhammad Ibrahim Biu, told the Nation newspaper.
He did not give further details.