Clashes have broken out in the capital of Gabon, Libreville, where President Ali Bongo won re-election earlier Wednesday in a vote that critics say was fraudulent.
Protesters are reported to have set the National Assembly building on fire, chanting "Ali must go!"
The Guardian newspaper reported that three people were "apparently shot dead by security forces." The government has not confirmed any deaths.
Opposition leader Jean Ping told AFP that Gabon security forces had stormed his party headquarters early Thursday, injuring 19 people, some of the "very seriously," he said.
A spokesman for the government said the security forces raided the opposition building in search of people who had set fires near the parliament building earlier in the night.
"Armed people who set fire to the parliament had gathered at Jean Ping's headquarters along with hundreds of looters and thugs... they were not political protesters but criminals," Alain-Claude Bilie-By-Nze told AFP.
Police are stationed at crossroads around the city.
VOA's Idrissa Fall, who is at the election commission headquarters, reports that some members of the electoral commission resigned Wednesday.
Bongo's main opponent, Jean Ping, has said his campaign has evidence the election was rigged and plans to present it to Gabon's constitutional court.
The official results, set to be formally announced, show Bongo winning 49.8 percent of the votes, with Ping at 48.2 percent.
At issue are the results from one province where the tallies show nearly 100 percent voter turnout, with Bongo receiving 95 percent of the votes.
U.N. Secretary-General Ban Ki-moon called for Gabon to remain peaceful in the aftermath of the hotly contested poll.
“The Secretary-General urges all concerned political leaders and their supporters to refrain from further acts that could undermine the peace and stability of the country,” his spokesman said in a statement. “He also calls on the authorities to ensure that the national security forces exercise maximum restraint in their response to protests.”
The U.S. Embassy called for all individual polling station results to be published after it said observers witnessed "many systemic flaws and irregularities" in the voting. The irregularities included polling stations opening late and "last-minute changes to voting procedures."
Both candidates declared victory after Saturday's vote, and each side accused the other of fraud during the vote count.
Gabon does not have a run-off system, so the candidate with the most votes in the 10-candidate field wins the election.
Ping was running to end a near half-century of Bongo family rule. Ali Bongo succeeded his father, Omar Bongo, who died in 2009 after 42 years in office.
Idrissa Fall and VOA Afrique contributed to this report.