Nigerian President Muhammadu Buhari said on Wednesday there were no doubts as to his re-election after his beaten rival promised a legal challenge against the result.

“From the comment of several observers, both local and foreign, it is obvious that the elections were both free and fair,” he said in a speech at the electoral commission.

Buhari’s second, four-year term was confirmed in results announced late on Tuesday, after a delayed election that sparked anger and claims of rigging and conspiracy.

The 76-year-old former military ruler, of the All Progressives Congress (APC), beat Atiku Abubakar, from the People’s Democratic Party (PDP), by 3.9 million votes.

But the PDP has accused the ruling party of conspiring with the electoral commission to manipulate the results. Abubakar called it a “sham election” and vowed to go to court.

Buhari’s comments came as he received his certificate of election at the Independent National Electoral Commission (INEC) in the capital, Abuja.

After shaking hands with commissioners, he said the election was “another milestone in Nigeria’s democratic development”, 20 years after the country returned to civilian rule.

Buhari’s victory in 2015 was the first time an opposition candidate had defeated an incumbent president at the ballot box.

In a short acceptance speech, he promised to build on his first term, which notably saw him tackle Boko Haram extremists and launch a high profile anti-corruption campaign.

That campaign has been criticized for being one-sided against his political opponents but he sought to reassure critics that his government would “engage all parties”.

“We have the best interest of Nigerians at heart... and we will work to deliver a better Nigeria,” he added.

Civil society groups monitoring the election said 53 people were killed in a weekend of political violence.

Buhari said Saturday’s vote was “overwhelmingly peaceful” and sent his condolences to the families of those who lost their lives.

“Elections are not war and should never be seen as a ‘do or die’ affair. I pray that all will accept this democratic approach to elections, however contentious,” he added.

Last Update: Wednesday, 20 May 2020 KSA 14:04 - GMT 11:04