Cameroon's 92-year-old leader, Paul Biya, has been sworn in for another seven years as president in a ceremony at the country's parliament in Yaoundé.

Biya won a controversial eighth term in a fiercely disputed election last month.

He has been in power for 43 years, and addressed only one campaign rally before the election.

The nonagenarian, the world's oldest head of state, won 54% of the vote, compared to the 35% of Issa Tchiroma Bakary, according to the official results. Tchiroma Bakary maintains he was the rightful winner of the poll and has accused the authorities of fraud, which they have denied.

The announcement of the result led to major protests across the country.

Reuters reported that 48 people lost their lives during protests across Cameroon, citing data shared by two United Nations sources.

Judges on the Constitutional Council had dismissed eight petitions, citing insufficient evidence of irregularities or a lack of jurisdiction to annul results.

Opposition candidate Issa Tchiroma Bakary whose wherabouts are unknown declared himself the winner - a claim rejected by the Cameroonian ruling party.

Earlier this week, Bakary's call for a stay at home protest was heeded by some people across Cameroon as streets were also deserted especially in his strongholds of Garoua and Douala.

The opposition leader was a former government spokesman who broke ranks with Biya to challenge him for power.

He refused to file complaints with the Constitutional Council, whose judges have been appointed by Biya.