Venezuelan authorities are committing "widespread human rights violations" against protesters, bystanders, and opponents in the aftermath of presidential elections the opposition says were stolen, Human Rights Watch (HRW) said Tuesday.

The NGO issued a report on the events that have transpired since July 28 elections in which incumbent President Nicolas Maduro claimed victory despite an outcry from the opposition and much of the international community.

It blamed Venezuelan authorities and pro-government armed groups known as "colectivos" for killings, arbitrary detentions and harassment of critics following the disputed vote.

Venezuela's National Electoral Council (CNE), most of whose members are friendly to 61-year-old Maduro, declared him reelected to a third six-year term despite opinion polls predicting victory for the opposition, which immediately cried foul.

The standoff sparked protests that led to the deaths of 25 civilians and two soldiers, according to official figures, with nearly 200 people injured.

The regime has blamed the opposition led by Maria Corina Machado and presidential candidate Edmundo Gonzalez Urrutia for post-election clashes that also saw more than 2,400 people arrested.

But HRW Americas director Juanita Goebertus pointed the finger at the regime, saying: "The repression we are seeing in Venezuela is shockingly brutal."

"Concerned governments need to take urgent steps to ensure that people are able to peacefully protest and that their vote is respected," she said in the report.

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

The CNE has said it cannot publish the records as hackers had corrupted the data, though observers have said there was no evidence of that.

Gonzalez Urrutia, a 75-year-old retired diplomat, replaced Machado on the ballot at the last minute after she was barred by Venezuelan institutions from running on charges widely dismissed as trumped up.

Both have mostly been in hiding since the election as Maduro has called for them to be locked up.

The opposition published its own polling station-level election results, which it says show Gonzalez Urrutia won the race by a landslide.

This prompted the filing of charges against the opposition candidate that include incitement to disobedience, sabotage, "association" with organized crime and financing of terrorism.

A court issued a warrant for his arrest Monday after Gonzalez Urrutia ignored three summonses in a row to appear before regime-appointed prosecutors investigating him.

'Repressive tactics'

HRW reported data obtained from local rights group Foro Penal of over 1,580 "political prisoners" arrested since July 29, including 114 children.

"Prosecutors have charged hundreds with sometimes broadly defined crimes carrying harsh sentences, such as 'incitement to hatred,' 'resistance to authority,' and 'terrorism'," it said.

HRW added that the government has also intensified "its broader repressive tactics," such as cancelling passports of critics to prevent them from leaving the country, encouraging citizens to report on demonstrators, and conducting abusive raids.

The NGO urged foreign governments to consider imposing further, targeted sanctions on members of the security forces and "colectivos," as well as on judges and prosecutors responsible for abuses.

HRW also said Maduro's allies, including Cuba and Venezuela's oil industry should be encouraged "to call on Maduro to... respect people's vote."

HRW called on the international community to expand access to asylum and other protections for Venezuelans fleeing the country.