The UN Human Rights Office said it "deplores" the executions, which were reportedly carried out by Iranian authorities last Friday.

The Iran Human Rights group said documents showed 17-year-old Hamidreza Azari died in Sabzevar Prison after he was alleged to have committed murder in April, when he was 16.

The group said the boy gave a "forced confession" and state media had reported his age to be 18.

"This is a deliberate attempt to evade accountability for violating international laws which explicitly prohibit the use of the death penalty against juvenile offenders," a statement from Iran Human Rights said.

UN Human Rights Office spokesperson Liz Throssell said it was "the first reported execution of an alleged child offender in Iran this year".

She added that the UN was "troubled" by the death of 22-year-old Milad Zohrevand who is "the eighth person to be executed in the context of the September 2022 protests".

"Available information indicates that his trial lacked the basic requirements for due process under international human rights law," Ms Throssell said.

"There are also troubling reports that Zohrevand's parents were arrested following his execution."

There were widespread protests in Iran in September 2022 following Mahsa Amini's death in police custody.

Ms Throssel reminded Iran of its obligation under international conventions "to prohibit death sentences and their implementation for crimes committed by individuals below the age of 18".

The UN has urged the Iranian government to "establish a moratorium" on the death penalty, adding it "may only be imposed for the most serious crimes, which refers to crimes of extreme gravity that result intentionally and directly in death".

It also called for Tehran to "stop using criminal procedures" to punish political activists and those exercising their rights to freedom of speech and peaceful assembly.

Read more:
Girl 'attacked for not wearing headscarf' dies
Activist could be sentenced to death in Iran

Protests broke out in Iran last year after Ms Amini died following her detention by morality police, who were enforcing the country's strict hijab rules.

Iran executed at least 582 people last year, the highest since 2015, with the majority carried out for murder and drug offences, according to Iran Human Rights.

At least three juvenile offenders and 16 women were executed, its report added.