A 16-year-old boy was killed and four other people were injured Monday when police in the Guinean capital Conakry opened fire in clashes with protestors, a doctor said.
The incident happened in the suburb of Sonfonia Gare, on a day of demonstrations called to oppose constitutional changes that could enable 81-year-old President Alpha Conde to seek a third term in office.
In the district of Cosa, an opposition stronghold, police fired stun grenades and teargas against groups of protesters, an AFP reporter saw.
An alliance of unions, opposition parties and civil society groups called the National Front for the Defence of the Constitution (FNDC) had appealed for a massive turnout.
Conde is a former opposition figure who in 2010 became the West African state's first democratically-elected president, but his tenure has been marred by a crackdown on protests.
Last month he called on the public to prepare for a referendum and elections, stirring speculation that he is planning to overcome a constitutional bar on a third term. The next presidential ballot is due to be held late next year.
The opposition says about 100 people have been killed since Conde took office in 2010, winning re-election five years later.
About 20 people have been arrested since Saturday, according to the FNDC.