Guinean soldiers fired on protesters with automatic rifles after the controversial re-election of the country's president last week, according to videos shared on social media.
President Alpha Condé, a former freedom fighter who once described himself as the 'Mandela and Obama of Guinea', won almost 60 per cent of the vote, the country's official election body announced on Saturday.
The victory grants the 82-year-old the right to begin his third term, which opponents have called a power grab in violation of the country's constitutional two-term limit. Mr Condé says a referendum in March legitimises his position.
The opposition candidate Cellou Dalein Diallo, who was reported to have garnered just over 33 per cent of the vote, urged his followers to take to the streets after he proclaimed the vote rigged and himself the rightful winner.
Videos on Twitter showed families crying over the shooting of their relatives and security forces vandalising the homes and property of protesters.
With reports of dozens of people killed in the unrest that has followed last Sunday's poll, analysts fear further bloodshed between the country's two main ethnicities - the Mandinka, the president's ethnicity, and the Fulani, Mr Diallo's.
Emissaries from the United Nations, the African Union and West Africa’s regional power bloc rushed to the country's capital Conakry on Sunday to try to defuse tensions.
Mr Condé became Guinea’s first democratically-elected president in 2010 after more than four decades as an opposition leader. He spent years in exile after he was imprisoned and tortured by Guinea's former dictator Lansana Conté.
When Mr Condé finally came to power, he was widely lauded as a champion of democracy by the likes of former British Prime Minister Tony Blair and Hungarian liberal activist and billionaire, George Soros. But in recent years the ageing president has grown more authoritarian in the hopes of hanging on power.