At least 34 bodies have been found in Burundi's capital after the worst night of violence in recent times.
Most of the bodies found on the streets of Bujumbura appear to be young men killed by gunfire, some with their hands tied behind their backs.
The bodies were found a day after attacks on military sites. Residents accuse police of taking revenge.
At least 87 people were killed in Friday's fighting, eight of them from the security forces, the army said.
Unrest has blighted Burundi since an attempted coup in May and protests over the president's continued rule.
The attempt to overthrow President Pierre Nkurunziza followed his decision to seek a third term in office, which he won in a disputed election in July.
BBC Africa analyst Richard Hamilton says bodies on the streets are almost a daily occurrence in Bujumbura but this is by far the largest number of deaths in one night.
The largest number of bodies found on Saturday were in Bujumbura's Nyakabiga district, a focus of anti-government protests.
Others were discovered in the southern neighbourhood of Musaga. There are reports of more bodies in other parts of the city.
Residents accuse the police of detaining young men during house-to-house searches on Friday and then murdering them.
But a police spokesman told Reuters there were no "collateral victims" and that those killed had been behind attacks on government installations.
Friday saw some of the worst violence since the unrest began. Officials described heavily armed attackers launching co-ordinated assaults on army installations in three areas - Ngagara, Musaga and Mujejuru.
An army spokesman said 12 insurgents were killed.
According to the UN, at least 240 people have been killed since April and more than 200,000 have fled to neighbouring countries.
There have been regular killings of both opposition activists and Nkurunziza supporters.
The violence has raised fears of a return to worsening ethnic tension between Hutus and Tutsis.
Mr Nkurunziza led a Hutu rebel group against the then Tutsi-dominated army during the civil war that followed the killing of Hutu President Melchior Ndadaye in 1993.
Timeline - Burundi crisis
April 2015 - Protests erupt after President Pierre Nkurunziza announces he will seek a third term in office.
May 2015 - Constitutional court rules in favour of Mr Nkurunziza, amid reports of judges being intimidated. Tens of thousands flee violence amid protests.
May 2015 - Army officers launch a coup attempt, which fails.
July 2015 - Elections are held, with Mr Nkurunziza re-elected. The polls are disputed, with opposition leader Agathon Rwasa describing them as a "joke".
November 2015 - Burundi government gives those opposing President Nkurunziza's third term five days to surrender their weapons ahead of a promised crackdown.
November 2015 - UN warns it is less equipped to deal with violence in Burundi than it was for the Rwandan genocide