The UN voiced outrage at the execution Thursday of a man in Iran who was only 16 when he committed his alleged crime, marking the fourth juvenile offender put to death in the country this year.
The UN human rights office said that Mohammad Hassan Rezaiee was executed early Thursday.
It did not provide further details about Rezaiee or the crime he was convicted of, allegedly committed when he was 16.
But according to Amnesty International, he was arrested in 2007 in connection with the fatal stabbing of a man in a brawl and had spent more than 12 years on death row.
"The execution of child offenders is categorically prohibited under international law and Iran is under the obligation to abide by this prohibition," UN rights office spokeswoman Ravina Shamdasani said in a statement.
The UN High Commissioner for Human Rights, Michelle Bachelet, "strongly condemns the killing," she added.
Shamdasani said the rights office was dismayed that the execution had taken place despite its efforts to engage with Tehran on the case.
"There are deeply troubling allegations that forced confessions extracted through torture were used in the conviction of Mr. Rezaiee," she said, adding that there were also "numerous other serious concerns about violations of his fair-trial rights."
She noted that Rezaiee's execution, the fourth of a juvenile offender in 2020, had come shortly after a series of other executions in Iran.
The December 12 execution of the France-based dissident Ruhollah Zam sparked an international outcry, with Western governments accusing Tehran of abducting him abroad to put him on trial.
And Shamdasani noted that at least eight people were executed at different prisons across the country between December 19 and 26 alone.
She warned that unconfirmed reports suggested that at least eight others were at risk of "imminent execution".
Many people convicted of committing crimes as minors are awaiting execution in the country.
"The UN has repeatedly urged Iran to cease the appalling practice of executing child offenders, but we understand that at least 80 child offenders remain on death row," Shamdasani said.
Bachelet, she said, "urges Iranian authorities to halt all executions of child offenders and immediately review their cases in line with international human rights law."