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 military ruler who briefly ruled the country in 1996.
He narrowly beat ruling party candidate Samura Kamara, who has alleged irregularities and says he will challenge the outcome in court.
Mr Maada Bio was sworn in on Wednesday, less than two hours after being declared the winner of Saturday’s vote.
Under Sierra Leone’s constitution, the presidential vote winner must be sworn in on the same day as he is declared the victor.
“[This is] the dawn of a new era,” he said.
“The people of this great nation have voted to take a new direction.
” In a televised address, Mr Kamara said: “We dispute the results and we will take legal action to correct them.
” He also urged his supporters to stay calm.
Mr Maada Bio, leader of the Sierra Leone People’s Party (SLPP), won just under 52% of the vote.
He has already ruled the country, albeit briefly.
The outgoing president, Ernest Bai Koroma, has stepped aside after serving two five-year terms for the All People’s Congress (APC).
He had hand-picked Mr Kamara as his preferred successor.
Mr Maada Bio lost to Mr Komora in the previous election.
Support for the SLPP and the APC is largely based on ethnicity.
The SLPP, the nation’s oldest party, is most popular in the southern and eastern parts of the country.