Guinea security forces fired live ammunition and tear gas at thousands of rock-throwing anti-government protesters in the seaside capital Conakry on Wednesday in clashes that wounded more than two dozen people, sources said.
The violence in the West African state is a result of soaring tensions ahead of a parliamentary election the opposition says is being rigged by the administration of President Alpha Conde.
"We don't know how it started, but the security forces charged the crowd and fired tear gas," said Ousmane Camara, a Conakry resident at the protest in the city's Hamdallaye neighborhood, an opposition stronghold.
Another witness said security forces had wounded at least two people, including a child, with live rounds and were using truncheons to push back other demonstrators, who threw stones and chunks of concrete, and set fire to tires.
A security official told Reuters on condition of anonymity that 16 police and gendarmes had been admitted to hospital with wounds after the initial clashes. Sources said injuries among the protesters were likely higher.
It was unclear if there were any dead, and witnesses said demonstrations were ongoing.
Guinea's opposition coalition had called for widespread protests in Conakry after announcing last week it would boycott preparations for long-delayed legislative polls, claiming the run up to the vote was flawed.
The election set for May 12 is intended to be the last step in Guinea's transition to civilian rule after two years under a violent army junta following the death of long-time leader Lansana Conte in 2008.
President Alpha Conde won a 2010 presidential election in the world's top supplier of bauxite, the raw material in aluminium, but delays in the legislative vote have deepened a political deadlock and led to intermittent violence.
The opposition says the elections commission chose the poll date unilaterally and that two companies contracted to update voter rolls have skewed the lists in Conde's favor. They also want Guineans living abroad to be allowed to vote.
Thousands of people had participated in peaceful protests across Guinea last week in support of opposition demands. The parliamentary poll was originally due to be held in 2011 but has already been delayed four times.
Conde has promised prosperity to the former French colony's 10 million people, whose economy produces only about $1.50 per person per day despite a wealth of natural resources, including the world's largest untapped iron ore deposit.
The European Union, a major donor, warned in November that it needed a credible and detailed timeline for the election to unblock about 174 million euros ($229 million) in aid.