Guinean police opened fire on anti-government protesters wounding several during violent clashes in the capital Conakry on Monday, medical and opposition sources told AFP.
Rioting broke out around 9:30 am (0930 GMT) in several suburbs including Simbaya and Hamadallaye, and angry protests continued as at least eight youths were treated for gunshot wounds.
The opposition had called for demonstrations in all parts of the capital against the ongoing lack of security for which it blames the regime of President Alpha Conde.
"There were violent clashes between young protesters and police in Hamdallaye, where security forces shot three young protesters," a hospital doctor said on condition of anonymity.
The medic told AFP two of the protesters sustained leg injuries while a third with a serious stomach wound was dragged several metres by police before being abandoned.
"He was quickly rescued by his comrades," a policeman told AFP.
The gunfire continued after the wounded were taken to hospital as youths rallied in the streets, according to an AFP correspondent on the ground who witnessed panicked residents trying to get home.
Four other protesters were wounded in the northeastern suburb of Simbaya, witnesses and a police officer told AFP on condition of anonymity.
Guinea's opposition boycotted parliament in March in protest over the timetable for a presidential election, accusing Conde of using the Ebola epidemic as an excuse to postpone voting.
Former prime ministers Cellou Dalein Diallo, Sidya Toure and Lansana Kouyate accused Conde of repeated rights violations and said he had "lost all legitimacy".
They called on supporters to back several demands including a call to bring forward local elections due in March next year.
Guinea, one of the poorest countries in the region despite vast potential for mineral exploitation, was run by a succession of autocratic rulers after gaining independence from France in 1958.
A military junta took control in 2008 after the of death of president Lansana Conte, who seized power in a coup 24 years earlier, and a caretaker regime oversaw the transition to civilian rule in 2010.
The last election -- September 2013's parliamentary vote -- was delayed by almost three years, stoking deadly ethnic tensions that have dogged the country's politics since independence.
Politics in Guinea typically polarises some two dozen ethnic groups who otherwise live in harmony alongside each other -- with the Fulani the largest at around 40 percent of the population followed by the Malinke and Soussou.
President Conde, a Malinke, leads the Rally of the Guinean People and claims to espouse socialism while his main rival, Diallo, is a Fulani and heads the centrist liberal Union of Democratic Forces of Guinea (UDFG).
Police had been deployed en masse early Monday to the planned locations of the rallies, declared illegal, at several main intersections across Conakry.
Amadou Damaro Camara, the chairman of the parliamentary majority group, accused the opposition of trying to create a "climate of instability".
"That is consistent with their desire to bring chaos to all areas," he told AFP.
El Hadj Aliou Bah, a UDFG lawmaker for the Ratoma constituency called on supporters to confront security forces, telling demonstrators: "We really do not have to be afraid of the police."
"Do not provoke anyone. When you are told to stop, stop. But when they attack you even though you are innocent, you don't just accept it, that much at least is clear," he added.