Hundreds of people marched through Central African Republic's capital on Friday, blowing whistles, denouncing fraud and demanding the first round of last month's presidential election be annulled.
The protesters, mostly young supporters of losing candidates in the turbulent former French colony, say hundreds of thousands of ballot papers were wrongly invalidated and want to start the poll again from scratch.
The vote was meant to help the country moved on from years of coups and sectarian conflict.
But the constitutional court this week canceled the result of a legislative election held at the same time as the presidential vote, citing irregularities.
Friday's protesters say the same should be done for the presidential vote, before a second round run-off vote scheduled for February.
"The aim of this peaceful march is to demand the constitutional court to cancel both polls since the same causes produce the same effects," said Josephine Ngbaboulou, spokesman for the Alliance of Democratic Forces for Transition, a coalition of parties supporting candidates who came third and fourth.
Marchers carried signs denouncing the constitutional court as police officers looked on. Demonstrations are officially banned during the election period.
Protesters gathered at the entrance the office of the UN peacekeeping mission in Bangui, saying they wanted the global body to press the court to act.
"So long as there is no response, we won't leave," said Dominique Yandoka, a youth leader for the Movement of the Liberation of Central African People party.
Former prime ministers Anicet-Georges Dologuele and Faustin-Archange Touadera are due to face off on Feb. 14 after neither won an outright majority in December. A re-run of the legislative election has been scheduled for the same day.
Observers had praised the peaceful nature of the polls but several presidential candidates submitted challenges to the court, saying polling was flawed and called for the vote to be annulled or recounted. The court dismissed them.
THe latest violence in Central African Republic erupted in early 2013 when mostly Muslim Seleka rebels seized power in the mostly Christian nation, provoking reprisals from Christian "anti-balaka" militias.
A transitional government was installed in 2014 but inter-comunal violence continued, driving nearly one fifth of the 5 million-strong from their homes.
The United Nations on Friday said it had allegations that peacekeepers from Georgia, France and another unnamed country sexually abused children while deployed in the country.
France, which sent about 900 soldiers to help restore order, is expected to resume a drawdown of troops once a new democratic government is inaugurated.
