Police and soldiers in the Democratic Republic of Congo have used force to block a planned rally calling for President Joseph Kabila to step down.
Rights group Human Rights Watch says two men have been shot dead outside a church in the capital Kinshasa.
Church activists and opposition parties had backed the demonstration.
Under a deal reached exactly a year ago, Mr Kabila should have stepped down by the end of 2017, a year later than originally scheduled.
An election to replace him has now been delayed until December 2018.
The authorities in Kinshasa banned the protest there, saying they did not have the resources to police it.
Police roadblocks have been in place since Saturday. The security forces have also used tear gas and live ammunition to prevent protesters from gathering at several locations, including churches.
About 50 people were arrested in Kinshasa and seven people were hurt by gunfire, Reuters quoted human rights activist Georges Kapiamba as saying.
A police spokesman denied the security forces had used live ammunition. He said protesters had been arrested for barricading roads and setting tyres on fire.
Mr Kabila has been in power since 2001. He was supposed to step down after his second and final term came to an end in 2016 but the vote to replace him was not held.
The failure to organise the polls led to a wave of deadly demonstrations by opposition supporters. The UN says dozens of people have been killed during anti-government protests over the past year.
A deal to create a transitional government brokered by the Catholic church collapsed because the government and the opposition were unable to agree on the power-sharing mechanism.