President Muhammadu Buhari is, at present, presiding over a meeting of the Council of State.
Former leaders absent are Ibrahim Badamasi Babamgida, Goodluck Jonathan, Shehu Shagari and Earnest Shomekan are absent.
Only Generals Yakubu Gowon and Abdulsalami Abubakar, as well as Chief Olusegun Obasanjo, are the former leaders present at the meeting.
Obasanjo, who was five minutes late, rushed to greet Buhari before taking his seat.
This is the third of such meeting since Buhari assumed office about three years ago. The first one was on October 21, 2015; and the second, September 7, 2016.
The meeting, which began at 11:05am, is being attended by Vice President Yemi Osinbajo and Senate President Bukola Saraki.
The closed-door meeting is expected to discuss the security challenges confronting the country.
Gowon and a former Chief Justice of Nigeria, Justice Mohammed Uwais, said the opening prayer.
Before the meeting started, President Buhari had gone round the Council Chambers to shake hands with his visitors.
The governors in attendance are those of Sokoto, Delta, Adamawa, Imo, Benue, Lagos, Nasarawa, Abia, Bauchi, Jigawa, Kebbi, Plateau, Kano, Wike, Akwa Ibom, Edo, Ekiti, Zamfara, Ogun, Niger, Ebonyi.
Former Chief Justices of Nigeria, Idris Kutigi and Aloma Muktar are also in attendance.
A one-minute silence was observed in honour of the late former Chief Justice of Nigeria, Justice Dahiru Mustapha.
The Council of State is an organ of the Federal Government saddled with the responsibility of advising the executive on policy making.
The council, which comprises president as chairman and vice president as deputy chairman, has as members; all former presidents and Heads of State all former Chief Justices of Nigeria, President of the Senate, Speaker of the House of Representatives, all state governors and Attorney-General of the Federation.
Its duties include advising the president in the exercise of his powers with respect to the National population census and compilation, publication and keeping of records and other information concerning the same; prerogative of mercy; award of national honours; the Independent National Electoral Commission (including the appointment of members of that Commission); the National Judicial Council (including the appointment of the members, other than ex-officio members of that Council); the National Population Commission (including the appointment of members of that Commission).
The council also advises the president whenever requested to do so on the maintenance of public order and on such other matters as the he may direct.