Venezuelan security forces have carried out hundreds of arbitrary killings under the guise of fighting crime, the UN's human rights body said on Friday.
In a report, it cites "shocking" accounts of young men being killed during operations, often in poor neighbourhoods, between 2015 and 2017.
The UN's human rights chief said no-one was being held to account, suggesting the rule of law was "virtually absent".
Venezuela has in the past dismissed human rights allegations as "lies", according to BBC.
The country is going through a protracted political and economic crisis.
Dozens of protesters were killed in clashes during anti-government protests last year and the country is also experiencing hyperinflation and food shortages.
President Nicolas Maduro was re-elected in May after the opposition boycotted the vote.
In the report, the UN Human Rights Council says the alleged extra-judicial killings were carried out by officers involved with the Operations for the Liberation of the People, ostensibly a crime reduction initiative.
These officers may have killed more than 500 people between July 2015 and March 2017 as a way to showcase crime-reduction results, it says. They are alleged to have faked evidence to make it look as though the victims died in an exchange of fire.
The officers involved have immunity from prosecution.
The UN High Commissioner for Human Rights, Zeid Ra'ad Al Hussein, called for an international investigation and has suggested the International Criminal Court could also become involved.
UN investigators have been denied access to Venezuela - a current member of the Human Rights Council - and made their findings from interviews with witnesses and victims.
Some of the other evidence comes from former attorney general Luisa Ortega. She was fired by Mr Maduro last year and went into exile.
Earlier this week the US quit the UN Human Rights Council, having previously criticised the body for failing to act against a number of countries, including Venezuela.
Mr Hussein has also accused Venezuela of failing to acknowledge the depth of its crisis, which has seen hundreds of thousands of people flee abroad.
"When a box of hypertension pills costs more than the monthly minimum wage and baby milk formula more than two months' salary, but protesting against such an impossible situation can land you in jail, the extreme injustice of it all is stark," he added.