Port Gentil is under a dusk-to-dawn curfew following a day of violence during which opposition demonstrators burned the French consulate and looted nearby shops. Prisoners in the port were broken out of jail.
The French Foreign Ministry says demonstrators attacked facilities owned by the French oil firm Total and the U.S. oil services company Schlumberger. The Foreign Ministry says there are no plans at present to evacuate French residents from Port Gentil, although all have been advised to remain in their homes.
Opponents of the ruling party rioted following the declaration that former Defense Minister Ali Ben Bongo won Sunday's presidential election.
Soldiers and opposition supporters clashed in the streets of the capital, Libreville. Politicians allied with opposition candidate Pierre Mamboundou say he was slightly injured in the unrest.
The violence follows days of delays in announcing final results of the vote because the electoral commission was split over its authority to investigate returns from nearly 3,000 polling stations
During that delay, all of the three leading candidates declared themselves the winner.
But when Interior Minister Jean Francois Ndongou announced the results on live television on Thursday, victory went to Mr. Bongo.
Ndongou says Mr. Bongo won nearly 42 percent of Sunday's vote. Mamboundou and former Interior Minister Andre Mba Obame each won more than 25 percent. That makes the ruling party candidate the winner because Gabon does not hold a run-off election if no candidate wins more than half of the ballots cast.
In an interview with VOA's French to Africa Service, Mr. Bongo was asked about winning an election in which more than half the voters cast their ballots for someone else.
The president-elect said that Gabon's plurality system is the same as the one used in the United States. Mr. Bongo said he will govern with a ruling party majority in both the Assembly and the Senate, and that he hopes all political parties will work together to develop the country.
Mr. Bongo ran the best financed campaign and was considered the front-runner since his father, Omar Bongo, died in June after 42 years in power.
Both Obame and Mamboundou are rejecting the election results. Obame says some ballot boxes were stuffed for the ruling party and that opposition supporters were excluded from the vote counting process. Mamboundou also accuses the ruling party of fraud, saying the Gabonese people do not want power passed dynastically from father to son.
African Union observers say the vote was held in a general atmosphere of calm and tranquility, despite irregularities that included the presence of security officers around the polls, confusion about electoral laws, the absence of officials during vote counting, and some ballot boxes not being properly sealed.
U.N. Secretary General Ban Ki-moon is urging calm and restraint by all concerned.
Former colonial power France says the vote took place under "acceptable conditions" and that losing candidates who want to contest the result should do so in Gabon's constitutional court.Mr. Bongo's election is not official until that court validates his win.