Gabon's president has narrowly won re-election, keeping alive a family dynasty in the oil-rich Central African country that reaches back five decades.
Clashes quickly broke out in the capital as opposition supporters claimed election fraud, looting and burning buildings.
President Ali Bongo Ondimba beat leading opposition candidate Jean Ping by just 1.57 percentage points, setting the stage for an almost certain challenge to the results.
Flames and smoke rose in the night sky from a large fire on a street in front of the National Assembly, according to residents nearby, who said that by late in the evening people had left the streets.
Demonstrators in several other districts vandalised a shopping mall, looted a bank and burned buildings, including one belonging to the vice prime minister, witnesses said.
Police had earlier fired tear gas at hundreds of opposition activists who converged near the Constitutional Court in the capital, Libreville, as army helicopters flew overhead.
Looting and clashes also followed Mr Bongo's win in 2009, when he came to power after the death of his father, long-time ruler Omar Bongo.
Ali Bongo won this election with 49.8% of the vote, while Mr Ping had 48.23%. The constitutional court must finalise the electoral commission's provisional results.
The results came a day later than expected, prompting fears of a tainted process.
European Union observers criticised a "lack of transparency," and the EU called for the electoral commission to publish the results from all polling stations.
UN Secretary-General Ban Ki-moon urged political leaders and their supporters "to refrain from further acts that could undermine the peace and stability of the country" and asked security forces to "exercise maximum restraint in response to protests," his spokesman said.
The US State Department urged calm and encouraged security forces to "act with both restraint and respect for the human rights of all Gabonese citizens".
Mr Bongo congratulated everyone for voting in peace and transparency, saying: "We are living in a moment where we must be more solid and more strong together."
Associated Press
