French President Nicolas Sarkozy sent his letter of congratulations to Ali Ben Bongo on his victory, according to the BBC. However, a joint call by 17 opposition candidates in Libreville called for serious scrutiny into the polls, Reuters reported.

"We demand a recount of the vote that was interrupted by the president of the electoral commission, on the basis of returns from all polling stations," the candidates, including runner-up former interior minister Andre Mba Obame, said in a statement.

They have called for an international probe into a crackdown by security forces on protesters, the Reuters said. "We call on the Gabonese people to remain mobilised and vigilant for progressive action," they said.

Media reports say France, the former colonial power, helped rig the vote. The French news agency AFP said Gabon officials showed journalists Mr Sarkozy's letter. "Following the announcement by the constitutional court of the presidential election results, I am happy to address to you my congratulations and wishes of success in fulfilling the responsibilities that await you," it said.

The French embassy in London confirmed to the BBC that a letter of congratulations had been sent by Mr Sarkozy. He went on to assure Gabon's president-elect of France's wish for good relations between the two countries, the report said.