Bongo received 49.8 percent of the vote, and his main rival, Jean Ping, received 48.2 percent, according to Gabon's Interior Ministry. While nationwide turnout was 59.6 percent, turnout in Bongo's home region of Haut-Ogooué was reported at 99.3 percent, prompting many to question the veracity of the results.
Photos taken Wednesday by Agence France-Presse photographer Marco Longari in the capital city of Libreville showed Ping supporters facing off against riot police.
Both France, which once ruled Gabon as a colony, and the United States released statements that voiced concern about the transparency of the election results and called for the results from each polling station to be made public.
The U.S. Embassy in Libreville said — via a somewhat contradictory Facebook post — that the election had been professional yet marked by "many systemic deficiencies and irregularities."
Riots broke out, too, in 2009 when Ali Bongo won his first election.
Bongo has sought to portray himself as a responsible leader who doesn't lead the lavish lifestyle his father was known for. Gabon has large oil reserves, and wealth from them has made the Bongos rich, even though much of the population still lives in poverty.
Jean Ping spent most of his life working in Omar Bongo's administration, as well as acting as chairman or president of large international bodies such as OPEC, the U.N. General Assembly and the African Union. He has portrayed himself as an agent of change after five decades of Omar and Ali Bongo.
Ping said in a statement that the people chose "our country’s next president" and that Bongo did not approve of their choice, "so he substituted his will for theirs."
He called on Bongo to "turn to peace and stop the violence by ordering our brothers, sisters and children in the security forces to attack our own."