At least four people have been fatally shot in the capital of the Central African Republic, according to hospital sources, as sectarian violence erupted on the city's streets for a second day.
Sunday's clashes were aimed at derailing elections scheduled to take place next month, the government said.
Armed Christian fighters roamed the streets and protesters erected barricades in Bangui, a day after at least 21 people were killed and another 100 were wounded when Muslims attacked a mainly Christian neighbourhood.
The two days of clashes, sparked by the murder of a Muslim man, were the worst this year in the city, where United Nations peacekeepers and French troops are meant to ensure security.
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"It's very sad to see violence of such a scale occur once again, as we haven't experienced anything like this since October last year," said Emmanuel Lampaert, the head of Doctors Without Borders' local mission.
Angry young men used tree trunks to block Bangui's main arteries early on Sunday. Soldiers from the UN peacekeeping mission, MINUSCA, fired tear gas at crowds in an unsuccessful attempt to clear the roads.
Witnesses reported hearing sporadic gunfire in parts of the city and saw homes and shops being looted.
The government on Sunday imposed a 12-hour curfew beginning at 6pm local time in an attempt to quell the violence.
"Enough is enough. We want [President Catherine] Samba-Panza to go. Since she's been there the Muslims kill with impunity. She's doing nothing to disarm them," said one protester who declined to give his name.
Thousands of Central Africans have died and hundreds of thousands remain displaced after two years of violence that erupted after mainly Muslim Seleka rebels seized power in the majority Christian country in 2013.
Seleka abuses sparked reprisals by Christian "anti-balaka" fighters that drove most Muslims from the south in a de facto partition of the country.
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Protesters alleged UN and French forces did little to intervene in Saturday's violence and called for the sidelined Central African army, the FACA, to assume responsibility for security.
"We are calling for a civil disobedience movement starting now and we demand the immediate redeployment, without conditions, of the FACA," said civil society leader Gervais Lakossa.
Anti-balaka fighters armed with assault rifles and machetes were seen on Bangui's streets on Sunday as many city residents fled their homes for protected displacement camps.
"The government asks the population not to cede to the manipulation of extremists who are seeking to set the country on fire to satisfy their selfish political ambitions," Security Minister Dominique Said Paguindji said on state radio.
Voters are due to elect a new president and parliament on October 18 to replace an interim government led by Samba-Panza.
Despite lagging preparations and the renewed violence in the capital, Paguindji said the polls would go ahead as scheduled.