Venezuela’s security forces and pro-government armed groups committed widespread abuses following the disputed presidential election in July, an international rights group has said.

The national guard, police force and armed groups known as “colectivos” killed 23 protesters during protests in the aftermath of the July 28 election, Human Rights Watch (HRW) said in a report on the post-election crackdown on Wednesday.

Thousands of people, including minors, took to the streets across Venezuela hours after electoral authorities, loyal to the governing party, declared President Nicolas Maduro the winner of the election, which the opposition said was stolen.

Maduro and allies of his United Socialist Party responded with full force, carrying out arbitrary detentions, prosecutions and a campaign – called Operation Tun Tun or Operation Knock Knock – encouraging people to report relatives, neighbours and other acquaintances who participated in the protests or cast doubt on the results.

“The repression we are seeing in Venezuela is shockingly brutal,” said Juanita Goebertus, Americas director at HRW. “Concerned governments need to take urgent steps to ensure that people are able to peacefully protest and that their vote is respected.”

The group said it had received “credible” evidence of the killings of 23 protesters and one member of the Bolivarian National Guard from “independent local groups”, including Foro Penal, Justicia Encuentro y Perdon, Monitor de Victimas and Provea.

Most of the killings occurred on July 29 and 30.

Eleven of the cases were “independently documented” by HRW, which said it reviewed death certificates, verified videos and photographs, and conducted interviews with 20 witnesses and local sources. It consulted forensic pathologists and arms experts, who analysed the injuries and weapons that were seen and heard.

Among the killings detailed in the report is that of civil engineer and food truck worker Rances Daniel Yzarra Bolivar, who was shot in the chest.

The report also included details of mass arrests during the protests. Venezuelan authorities have said more than 2,400 people were arrested since July 29, including children, journalists, political leaders, campaign staffers and a lawyer defending protesters. One local activist livestreamed her arrest by military intelligence officers as they broke into her home with a crowbar.

Local group Foro Penal reported that 114 children had been arrested. At least 86 children have been released, some subject to periodic court appearances.

HRW said those arrested were often kept incommunicado for weeks and most have been denied the right to hire a lawyer.

Global condemnation

The National Electoral Council declared Maduro had been re-elected for a third six-year term, declining to release vote tallies backing his victory.

But the main opposition coalition obtained vote tallies from more than 80 percent of the electronic voting machines and said its candidate, Edmundo Gonzalez Urrutia, defeated Maduro by a 2-to-1 margin.

The lack of transparency in the results, coupled with the arrests that followed the antigovernment protests, has drawn global condemnation against Maduro and his allies. The criticism grew on Monday after a judge approved a prosecutor’s request for an arrest warrant for Gonzalez.

The United States, the European Union and several Latin American countries have refused to recognise Maduro’s victory without seeing a detailed breakdown of votes cast.