Police in the Democratic Republic of Congo have fired tear gas at stone-throwing demonstrators as tensions rise over the timing of the next election.
Clashes erupted in the capital, Kinshasa, and the eastern city of Goma, where a policewoman and a protester were killed, the UN says.
But local officials have denied the police death.
President Joseph Kabila's opponents are concerned that he will not step down in December, the end of his second term.
A presidential election is due in November, but this could be delayed.
Earlier this month the Constitutional Court ruled that the president could stay in power if no election took place.
The BBC's Maud Jullien says that some see this as part of a ploy to allow Mr Kabila to extend his presidency.
Oppositions groups had called for the protests after the Constitutional Court's ruling.