At least 10 people have died in clashes between police and demonstrators in the Democratic Republic of Congo.
Voter registration has only just begun and could take months
Police fired live bullets and tear gas as thousands of opposition supporters rioted in the capital, Kinshasa, over a delay to presidential elections.
Elections were due before the end of June under the terms of a peace deal, but MPs have backed a six-month delay.
Voter registration problems, clashes in the east and government in-fighting prompted the postponement.
In an address to the nation, President Joseph Kabila promised a swift end to the lengthy transition period.
After MPs voted for the six-month delay, earlier this month, it was then announced that presidential and parliamentary elections would not be held until March next year.
According to the BBC's Arnaud Zajtman in Kinshasa, a number of other protesters were wounded and opposition figures said 100 of their supporters were arrested by police.
In his national address marking the 45th anniversary of Congolese independence from Belgium, Mr Kabila said changes which had been going on for 15 years had failed to improve things for normal people.
"I am determined to put an end to the spiral of endless transitions and give the people the opportunity to freely choose those who should preside over their destinies," he said.
But our correspondent says people on the streets of the capital say they do not trust the president or the current government.
Elections should have taken place by the end of June under the terms of the 2002 peace agreement, which ended a civil war which led to millions of deaths.
Sporadic ethnic conflict is still taking place in the east, despite the presence of the world's largest United Nations peacekeeping force.
President Kabila came to power after his father, Laurent - who overthrew long-time ruler Mobutu Sese Seko - was assassinated in 2001.
The demonstrators are supporters of the Union for Democracy and Social Progress (UDPS) an opposition party which fought dictatorships in DR Congo for decades through peaceful means but never made it to power.
Joseph Kabila is under pressure from donors
The peace agreement helped set up a power-sharing government, which includes former rebel groups, but the UPDS is not part of the transitional administration.
The party is led by veteran politician Etienne Tshisekedi, who headed the opposition to former President Mobutu. It is boycotting the voter registration process.
Officials say it might take at least four months for the estimated 28 million voters to be registered in the vast country.
Lack of progress in the peace process and mistrust between the parties and government, along with poor infrastructure, mean that elections remain a distant prospect, our correspondent says.