Sierra Leone's opposition candidate, Julius Maada Bio, has rushed to take his presidential oath in a hotel after winning the run-off election.

Mr Maada Bio is a former soldier who briefly ruled the country in 1996.

He narrowly beat ruling party candidate Samura Kamara, who has challenged the result, allegedly irregularities.

Mr Kamara, an economist by training, said he will challenge the outcome in court.

Mr Maada Bio took the oath in the capital Freetown on Wednesday after winning just under 52% of the vote.

President Ernest Bai Koroma has stepped aside after serving two five-year terms.

Mr Maada Bio, who is leading the main opposition Sierra Leone People's Party (SLPP), lost to Mr Koroma in the last election. But Mr Maada Bio had already ruled the country briefly.

The 53-year-old was part of a group of soldiers who overthrew the government in 1992. Four years later he staged another coup and ruled Sierra Leone between January and March 1996.

His supporters point to that to call him the "father of democracy".

But his critics cite human rights violations witnessed while he was in power, for which he has taken "collective responsibility".

A hard road ahead

By Umaru Fofana in Freetown

It has been a sometimes acrimonious campaign with the defeated candidate's party accusing the electoral commission, foreign observers, civil society and journalists of being a part of an international conspiracy to hand the election to Mr Maada Bio.

Even with the country's deep-rooted ethnic politics, tribalism came to the fore more prominently than ever before.

With a narrow outcome, the new president has vowed to heal the divisions, and build back the country's broken educational system. He has a tough job ahead of him, made harder by the fact that his party is a minority in parliament.