Leaders of Economic Community of West African States are scheduled to gather in Abuja on Monday to brainstorm on how to achieve a peaceful handover of power on January 19, this year.
Buhari who is hosting four other leaders is expected to preside over the strategic meeting.
In a statement by the Presidency on Sunday night and signed by Garba Sheu, he said Presidents of Liberia and Senegal, the Vice President of Sierra-Leone and ex-President Mahama are expected at the meeting.
President Muhammadu Buhari (PMB) had earlier assured that Nigeria would do everything possible to help The Gambia have a peaceful resolution to its political crisis.
He spoke through the Minister of Foreign Affairs, Geoffrey Onyema, last Wednesday in Abuja.
He expressed optimism that The Gambian President Yahya Jammeh would listen to the voice of his people to resolve the political impasse in his country.
President Jammeh had recently accused West African regional body, ECOWAS of declaring war against his country, when he was asked to step down for president- elect Adama Barrow.
Jammeh, who accused ECOWAS of putting forces on alert in case he refused to step down, had vowed to stay in power in spite of losing December 1, 2016 election to rival Adama Barrow.
He also promised to defend The Gambia against any outside aggression in a New Year speech broadcast on state TV.
The Gambian president initially conceded defeat in the vote but later changed his mind, raising fears that regional powers might have to intervene to oust him.
They had also met in Accra Ghana at the weekend while another meeting is scheduled for Monday.
In the statement issued by Garba Sheu on the Monday meeting, he said “ In furtherance of his mandate as mediator, the President of the Federal Republic of Nigeria, Muhammadu Buhari will be hosting four other West African leaders to a meeting aimed at avoiding violence and preserving democracy in The Gambia.
“President Buhari and the immediate past President of Ghana, John Mahama as Mediator and Co-Mediator respectively, have also been mandated by the Economic Community of West African States (ECOWAS) to ensure the safety of the President-elect, Adama Barrow and ensure a peaceful handover of power on January 19.
“The meeting in Abuja is following the one in Accra on the sideline of the inauguration of that country’s President which expressed the readiness of the leaders of the sub-region to continue the pursuit of dialogue with the leaders of The Gambia.
“The Presidents of Liberia and Senegal, the Vice President of Sierra-Leone and ex-President Mahama are expected at the meeting,” he signed off.