(AFP) - Gabon's constitutional court is to rule as early as Friday who will be the country's next president, ending weeks of uncertainty after disputed polls sparked a political crisis and violent protests.

Incumbent President Ali Bongo, the son of late autocratic ruler Omar Bongo, was declared the winner of the August 27 election by a margin of fewer than 6,000 votes.

But rival Jean Ping, a career diplomat and former chairman of the African Union Commission, filed a legal challenge and demanded a recount, saying that the vote was fraudulent.

The court met Thursday and had retired to consider its verdict. It has the choice of either upholding the original result or overturning it.

"The case is under deliberation. In principle, the decision could be handed down on September 23," the president of the court, Marie-Madeleine Mborantsuo, said at the end of a nearly three-hour hearing on Thursday.

Ping's entourage has accused the court and Mborantsuo of already being guilty of a "miscarriage of justice", citing an interview she gave.

"I have to say that it is rare that the choice of reversal (of the vote results) is used," she told the weekly Jeune Afrique on September 15 -- a statement that infuriated the pro-Ping supporters.

Mborantsuo, a former beauty queen from Bongo's stronghold of Haut-Ogooue, caught the attention of late leader Omar Bongo and was named to the country's top court when she was only 28.

She had an affair with him and bore him two children. According to the opposition and the Gabonese media, she has amassed a large property portfolio at home and abroad.

"Nobody wants to be in Mborantsuo's shoes," said a diplomatic source. "She is under enormous pressure from both camps."

Ping has made clear he believes Bongo has the court in his pocket, referring to it as "the Tower of Pisa that always leans the same way".

- 'Clear anomaly' -

Friday marks the expiry of a 15-day deadline for the court to resolve the electoral dispute, but the announcement could still be delayed until Saturday.

The small west African nation of 1.8 million people has been deeply split by violent protests that erupted after Bongo was declared the winner.

In his legal challenge, Ping asked for a recount in Haut-Ogooue province, a stronghold of the Bongo family who have ruled Gabon since 1967. Bongo won more than 95 percent of votes there on a declared turnout of more than 99 percent.

Following the poll, EU election observers said there had been a "clear anomaly" in the results from the province.

Security forces deployed in the capital Libreville Thursday where the situation was tense as people awaited the court's decision, with officers in riot gear, prepared to head off any more unrest should the judges decide against Ping.

Gabonese ministers, who have vowed to maintain order, warned the 73-year-old that his actions could be held responsible if fresh violence breaks out.

Ping's supporters say "more than 50" people were killed in post-electoral violence but the interior ministry has put the toll at three dead.

Locals were stockpiling food to last through the weekend should the streets be manned with checkpoints.

On Tuesday, lawyers for the two sides said they had agreed to a recount although they disagreed over the scope of it.

© 1994-2016 Agence France-Presse