The UN has warned that possible "crimes against humanity" may have been committed in Venezuela, which is currently facing a crisis.
Violence erupted in the country in April, in the lead-up to a controversial election for a new constituent assembly.
The vote, which took place in July, sparked widespread anti-government protests exacerbated by anger due to an ongoing financial crisis that has led to unemployment alongside dire food and medicine shortages.
Among other demands, protesters called for President Nicolas Maduro to step down as they blame him for the country's crippled economy.
More than 120 people have been reported killed in four months of unrest and Venezuela has been repeatedly accused of using excessive force to quell demonstrations.
"My investigation suggests the possibility that crimes against humanity may have been committed," UN High Commissioner for human rights, Zeid Ra'ad Al Hussein, was quoted by AFP as saying.
He also called on the the UN Human Rights Council to set up an international investigation into the alleged rights violations in Venezuela.
Last month, Zeid's office said that democracy was "barely alive" in the country.
In July, Venezuelans voted in favour of the new constituent assembly that can rewrite the country's constitution and override the opposition-controlled congress. The result of the election sparked a new round of protests and deaths.
Maduro hailed the election result, with the government claiming that more than eight million people – or 41% of the country's electorate – voted in favour of a new assembly that
The opposition, which accuses Maduro of trying to tighten his grip on power, refuted the claim, arguing the election was rigged.
Venezuela has attracted criticism over alleged human rights abuses and has been hit by sanctions from the European Union and the US.
Last year, the country was suspended from the regional trade bloc Mercosur for violating the organisation's democratic principles. Caracas described the suspensions as a coup attempt. The bloc is composed of Argentina, Brazil, Paraguay and Uruguay.