Guinea is voting to elect a new president amid violent clashes between opposition and pro-government supporters.
Seven candidates are competing against President Alpha Conde, who is hoping to win a second term.
The 2010 election saw a transition from military to civilian rule.
Since then Guinea has been badly hit by an Ebola outbreak and seen prices of key export bauxite – the raw material in aluminum – slump.
Opposition parties had wanted the vote postponed due to alleged anomalies in Guinea’s electoral roll, but this has been rejected by the election commission.
At least three people have been killed in pre-election violence.
Alpha Conde is favorite to win the election but a second round of voting is likely.