Security forces in Guinea have clashed with demonstrators, calling on President Lansana Conte to resign on the 13th day of a general strike.
The protesters say they will continue until the president steps down
At least 17 people died in running battles with police in the capital, Conakry and other towns. Ten people were killed in clashes last week.
A BBC correspondent says many thousands took to the streets in the biggest protests since the strike began.
Marchers were chanting "Enough" and "Bye Bye Conte".
Guinea's unions and opposition parties say President Conte is too sick to govern.
The strikers also accuse Mr Conte of mismanaging the economy and personally securing the release from prison of two men accused of corruption.
Some 30,000 demonstrators matched through Conakry, heading for the parliament building.
They were blocked at the 8 Novembre bridge, which separates central Conakry from the suburbs, by security forces, who opened fire, witnesses say.
"There are at least 100 injured. The number of dead can be estimated at 11, but we have to finalise the count... the injured are still coming in," a doctor in Conakry's Donka Hospital told Reuters news agency.
Deaths have also been reported in the town of Siguiri and Kankan.
There were also mass protests in the towns of Pita, Dabola and Telemele, reports the AFP news agency.
On Saturday, Mr Conte made a speech on television, asking for the support of the people and the army.
"Those who want power must wait their turn. It is God who gives power and when he gives it to someone, everyone must stand behind him," he said.
"Guineans must remain united, above all us soldiers, because we must be proud of wearing the uniform, a sign of allegiance to defending the country."
UN Secretary-General Ban Ki-moon and the African Union head Alpha Oumar Konare have called for dialogue between the two sides.
Mr Ban said he was concerned about the loss of life during the protests.
Presidents Abdoulaye Wade of Senegal and Olusegun Obasanjo of Nigeria are expected to go to Guinea to try and mediate.
The strikers were prevented from reaching the city centre
Food prices are said to have risen sharply in Conakry, with shortages of staple foods including rice and bread.
Hundreds of people are said to have been arrested since the strike began.
Mr Conte seized power in a 1984 coup but has since won three elections.
He is in his 70s but suffers from diabetes.
The current general strike is the third in the last year.