Two people have been killed in overnight clashes between demonstrators and security forces in Gabon's capital Libreville after disputed elections.
The deaths bring the number killed to five following a second day of violence.
Security forces in Gabon have arrested more than 1,000 people since the presidential vote.
Protests began after Wednesday's announcement that President Ali Bongo had narrowly been re-elected.
Too many voters? By Elizabeth Blunt, former BBC journalist and election observer
You never get a 98% or 99% turnout in an honest election. You just don't.
Voting is compulsory in Gabon, but it is not enforced; even in Australia where it is enforced, where you can vote by post or online and can be fined for not voting, turnout only reaches 90-95%.
The main reason that a full turnout is practically impossible is that electoral registers, even if they are recently compiled, can rarely be 100% up-to-date.
Even if no-one gets sick or has to travel, people still die. And when a register is updated, new voters are keen to add themselves to the list.
No-one, however, has any great enthusiasm for removing the names of those who have died, and over time the number of these non-existent voters increases.
The UN, which has expressed "deep concern" over the escalation of violence, joined the US and former colonial power France in calls for restraint and greater transparency about the election results.
"I know who has won and who has lost," Mr Bongo told local media.
"Who has won? 1.8m Gabonese with whom we will progress together. Who has lost? A small group which had the objective of taking power to use Gabon instead of serving it."
Interior Minister Pacome Moubelet Boubeya said on Thursday that 800 people had been arrested in Libreville and 400 in other areas of the country.
Thursday saw a second day of rioting, with police using tear gas to prevent crowds gathering at the national assembly building which was earlier set on fire by protesters.
Meanwhile, President Bongo's rival Jean Ping told the BBC that a presidential guard helicopter had bombed his headquarters and killed two people.
He has gone into hiding and is said to be safe.
Gabon election: Bongo v Ping
- Mr Bongo (pictured left) took office in 2009 after an election marred by violence
- He succeeded his father Omar Bongo who had come to power in 1967 and was Africa's longest serving leader
- Veteran diplomat Mr Ping had served as chair of the African Union
- He had been a close ally of Omar Bongo and had been his foreign minister
- He had two children with Omar Bongo's daughter, Pascaline
The official election result from Saturday's election gave Mr Bongo a second seven-year term with 49.8% of the vote to Mr Ping's 48.2% - a margin of 5,594 votes.
But Mr Ping said the vote was fraudulent.
He cited the result in Mr Bongo's home province of Haut-Ogooue, where turnout was 99.93% and 95% of votes were for the president.
Mr Bongo took office in 2009 after an election marred by violence, succeeding his father Omar Bongo who had come to power in 1967.
Mr Ping had been a close ally of Omar Bongo, serving him in ministerial roles and having two children with his daughter, Pascaline, a former Gabonese foreign minister.