Bola Tinubu sworn in as Nigeria's new president

Long-time political kingmaker Bola Tinubu has been sworn in as Nigerian president succeeding Muhammadu Buhari, a former general who stepped down after two terms in office.

The former governor of Lagos, Nigeria’s economic hub, Tinubu, 71, was sworn on Monday in the capital city, Abuja, in the presence of thousands of Nigerians and several heads of governments.

He takes over the reigns of the government from the 80-year-old northerner as Africa's most populous nation faces a sea of economic troubles and a security crisis.

"As president of the Federal Republic of Nigeria I will discharge my duties and perform my functions honestly to the best of my ability, faithfully and in accordance with the constitution," Tinubu said, in a live broadcast from the capital Abuja 's Eagle Square.

Foreign leaders and representatives present at the ceremony included presidents Cyril Ramaphosa of South Africa, Paul Kagame of Rwanda and Nana Akufo-Addo of Ghana as well as delegations from the US, Britain and China.

Kashim Shettima was sworn in as vice president, taking over from Yemi Osinbajo.

The ruling party duo were declared winners of the February 25 election, gaining 8.8 million votes and picking up the required number of ballots across two-thirds of Nigeria's states.

The main opposition leader Atiku Abubakar, who came second, and outsider Peter Obi, who was third, are contesting the results in court, claiming fraud.

The electoral commission has acknowledged "glitches" during the vote but dismissed claims that the process was not free and fair.

Dubbed a political "godfather", Tinubu campaigned saying "it's my turn" to govern Nigeria, Africa's biggest economy.

He touted his experience as Lagos governor from 1999 to 2007 -- a period that, supporters say, modernised Lagos, Nigeria's business hub.

But the new president also faces corruption allegations, which he denies, and questions over his health.

Coming from the ruling All Progressives Congress, which has been dogged with allegations of corruption, Tinubu's emergence as Nigeria's president-elect has also drawn concerns about how transparent he would be in office.

Although he has often talked about assembling the best hands to lead Nigeria, the nation's problem has never been about the quality of public officials but about accountability, said Leena Koni Hoffmann-Atar, associate fellow in the Africa program at the Chatham House think tank.

“What we underestimate is that for state institutions to be strengthened, beyond the character and competence of the individuals, you have to have processes of accountability.