Guinea security forces killed at least seven protesters this week during demonstrations against a possible change to the constitution that could let President Alpha Conde seek a third term, hospital staff in the capital Conakry said.
Police opened fire on demonstrators on Monday as they ransacked military posts and blocked roads with burning tyres in Conakry and protests in the northern opposition stronghold of Mamou also turned violent, witnesses said.
Protests have continued since Monday with decreasing intensity.
"We have received seven bodies in various hospitals since Monday, all were killed on the spot or shot and wounded before succumbing to their injuries later," a medical officer told Reuters.
Government spokesman Amara Somparé confirmed that seven people had been killed without providing further detail.
"We are currently conducting investigations to get the exact data that can explain the circumstances of these deaths," he said.
A coalition of opposition groups said on Wednesday that in all 10 people had been killed since Monday. It provided a list of the dead that included a 14-year-old schoolboy called Boubacar Diallo.
It said in a statement that 70 people had been wounded by bullets and that 200 people had been arrested.
Conde's second and final five-year term expires in 2020 but the 81-year-old leader has refused to rule out running again. He asked his government last month to look into drafting a new constitution, raising concerns that he might use it as a reset button on his presidency and run again.
Extending his mandate would mark a turnaround for Conde who as an opposition leader railed against militarised, autocratic regimes.
His first election win in 2010 raised hopes for democratic progress in Guinea after two years of military rule and nearly a quarter a century under authoritarian President Lansana Conte, who died in 2008.
However, tinkering with term limits or eliminating them altogether has been part of the playbook of African rulers even during a recent push towards democracy in parts of the region.
Rwanda's Paul Kagame and Congo Republic's Denis Sassou Nguesso easily pushed through new constitutions in 2015 that allowed them to stay in power.
Even measures ostensibly passed to introduce term limits have been used to extend mandates.
In Chad, a new constitution passed last year reimposed a two-term limit scrapped in a 2005 referendum. But it will not be applied retroactively, meaning President Idriss Deby could serve two six-year terms after the next election in 2021.
A change in Togo's law voted through in May capped mandates to two five-year terms. But like Chad it was not retroactive and could allow longstanding President Faure Gnassingbe to stay in power until 2030, extending his family’s rule to 63 years.