Iran executed nearly 1,000 prisoners last year, the highest number in two decades, and hundreds of journalists, activists and opposition figures languish in custody, a United Nations investigator said on Thursday.
Ahmed Shaheed, U.N. special rapporteur on human rights in Iran, voiced particular concern about executions for crimes committed by children under 18. This was "strictly and unequivocally prohibited under international law".
There had been a "staggering surge in the execution of at least 966 prisoners last year - the highest rate in over two decades", Shaheed told a news briefing.
"A large percentage of those executions are for drug offences and under Iran's current drug laws, possession of 30 grams of heroine or cocaine would qualify for the death penalty. So there's a number of draconian laws," he said.
Corruption and certain sexual activities can also qualify for the death sentence in the Islamic Republic, he added.
"The number of juvenile offenders executed between 2014 and 2015 - which is reportedly 16 - was higher than at any time during the past five years," Shaheed said.
But he welcomed efforts to address some problems related to juvenile justice. These include reforms allowing judges to assess a juvenile's mental capacity to determine whether they understood their actions at the time.
The U.N. Committee on the Rights of the Child said last month that Iran must reform laws that allow girls as young as nine to be executed for crimes or forced into sexual relations with older husbands.
"Fundamental problems also exist with regard to the due process and fair trial rights of the accused," Shaheed said.
"I continue to receive frequent and alarming reports about the use of prolonged solitary and incommunicado confinement, torture and ill-treatment, lack of access to lawyers and the use of confessions solicited under torture as evidence in trials - practices that clearly violate Iran's own laws," he said.
Hundreds of journalists, bloggers, activists and opposition figures "currently languish in Iran's prisons and detention facilities," he said.
Shaheed is a former foreign minister of the Maldives who has served in the independent post since 2011. He has never been allowed into Iran but his report was based on 128 interviews with Iranians abroad and in the country.