Buhari said henceforth Nigerians "shall be able to go to bed knowing that you are safe and that your constitutional rights remain in safe hands."

He added: "you shall be able to voice your opinion without fear of reprisal or victimisation. My love and concern for this nation and what I desire for it extends to all, even to those who do not like us or our politics. You are all my people and I shall treat everyone of you as my own."

"I shall work for those who voted for me as well as those who voted against me and even for those who did not vote at all. We all live under one name as one nation: we are all Nigerians," he said.

Buhari, 72, said despite the rancour of the elections, "I extend a hand of friendship and conciliation to President Jonathan and his team. I hereby wish to state that I harbour no ill will against anyone."

He said he would be guided by the rule of law, adding that "I pledge myself and our in-coming administration to just and principled governance. There shall be no bias against or favouritism for any Nigerian based on ethnicity, religion, region, gender or social status.

"I pledge myself and the government to the rule of law, in which none shall be so above the law that they are not subject to its dictates, and none shall be so below it that they are not availed of its protection."

He hailed President Jonathan who conceded defeat for demonstrating sportsmanship.

He said there shall no longer be a ruling party again: "APC will be your governing party. We shall faithfully serve you. We shall never rule over the people as if they were subservient to government," he said.

On Boko Haram insurgency, he said, though the task is tough, "I assure you that Boko Haram will soon know the strength of our collective will and commitment to rid this nation of terror, and bring back peace and normalcy to all the affected areas. We shall spare no effort until we defeat terrorism."

On corruption, he said "corruption attacks and seeks to destroy our national institutions and character. By misdirecting into selfish hands funds intended for the public purpose, corruption distorts the economy and worsens income inequality. It creates a class of unjustly-enriched people."

"Such an illegal yet powerful force soon comes to undermine democracy because its conspirators have amassed so much money that they believe they can buy government. We shall end this threat to our economic development and democratic survival," he said.

Buhari was accompanied to the event by his wife, Hajiya Aisha, the Vice President-elect, Professor Yemi Osinbajo and top APC leaders.