Sporadic gunfire echoed across Democratic Republic of Congo's capital on Wednesday, the day after security forces killed at least 26 protesters demanding President Joseph Kabila step down after his mandate as elected leader expired.
A government spokesman could not be reached to comment on the nationwide death toll, compiled by New York-based Human Rights Watch (HRW), which said it was yet to give a final tally.
The United Nations human rights director for the vast central African state said it had "solid" reports of at least 20 dead civilians in the capital, Kinshasa.
Some Kinshasa residents ventured from their homes on Wednesday morning but most streets were clear of traffic and public transport was extremely limited.
Africa and the West fear the political crisis around Kabila could spiral into a broader conflict, triggering a repeat of the 1996-2003 wars that killed millions and sucked in half a dozen neighbouring countries' armies.
The former Belgian colony has never experienced a peaceful transition of power.
The main opposition bloc gave mixed signals about whether it would return on Wednesday to talks mediated by Congo's Catholic bishops, with a final decision expected during the morning.
Protests had erupted in the early hours of Tuesday, moments after the expiry of Kabila's mandate cast the nation of 70mn into the constitutional unknown. Elections to choose a successor were delayed from November this year to mid-2018.
Gangs of mainly young men burned tyres in the streets of Kinshasa and threw stones at riot police and soldiers who responded with live rounds and teargas.
Clashes also happened in the southeastern mining city of Lubumbashi and the western port cities of Matadi and Boma, and Goma in the east, next to the border with Rwanda.
Scores of arrests were made in Kinshasa and other cities.
A police spokesman said he did not yet have information on the number of deaths or arrests.
Kabila's government blamed delays in the election on problems with registering millions of voters, and the constitutional court ruled in May that Kabila could stay in power until the delayed vote in April 2018.
However, the main opposition faction in parliament refused to endorse the deal to allow him to stay on. Opposition leader Etienne Tshisekedi called on Congolese people on Tuesday to peacefully resist Kabila.
The opposition says Kabila is deliberately delaying the poll in order to cling to power - a charge he denies.
Residents chant slogans against Congolese President Joseph Kabila during demonstrations in Kinshasa on Tuesday.