Seventeen people were killed during violent protests against a postponement of presidential elections in Congo, the interior minister said Monday.
Among the dead are 14 civilians and three police officers, Interior Minister Evariste Boshab told journalists in the capital, Kinshasa.
At least 57 people were injured during the protests, according to the Access to Justice Association.
More than 50 protesters were arrested across the country, the monitoring group said.
Congo's electoral commission requested the constitutional court consider postponing November elections last week, saying preparations could not be completed in time.
In protest, tens of thousands of opposition supporters took to the streets in several cities across the central African nation on Monday, blocking roads with burning tires.
President Joseph Kabila's second term in office will end on December 19. A new election date has not yet been set and the opposition is concerned the 45-year-old ruler is trying to extend his rule.
Under Congo's constitution, Kabila is not eligible to seek a third term.
"We are protesting to tell [Kabila] enough is enough," opposition leader Martin Fayulu told dpa.
Protesters in Kinshasa and in the second-largest city, Lumbumbashi, blocked roads while holding banners that read, "Respect the constitution," and "Kabila must quit and go," witnesses said.
Police used live bullets against peaceful demonstrators, they added.
Opposition members clashed with police in the eastern city of Goma, and police responded with teargas to disperse them.
UN Secretary General Ban Ki-moon condemned the violence and expressed "deep concern," his spokesman said. Ban urged all parties to refrain from any further violence.
US State Department spokesman John Kirby said the US was "deeply alarmed" by the violence and that the events "underscore the need for a truly inclusive dialogue process" on holding elections as soon as was feasible.
The protests come after Congo's largest opposition parties rejected a proposal that Kabila remain in power until elections are held.
According to the constitution, the electoral commission must call for presidential elections 90 days before the end of a president's mandated term.