Iran had a "deeply troubling" number of executions last year and did not keep a promise to protect ethnic and religious minorities, the United Nations said on Tuesday in its annual report on Tehran's human rights record.
The report from the office of Secretary-General Ban Ki-moon to the UN Human Rights Council catalogued UN concerns about rights violations in Iran against women, religious minorities, journalists and activists.
The report was published as a deadline nears for Iran and major powers to agree a deal on its nuclear program, which Tehran says would end sanctions against it.
Iranian Foreign Minister Mohammad Javad Zarif complained to the Council on Monday about "double standards" and an "almost uncontrollable compulsion" to politicize issues.
Iran was believed to have executed at least 500 people between January and November 2014 and possibly many more, the report said. Most victims did not get a fair trial and over 80 percent of those executed were drug offenders, it said.
"The Secretary-General remains deeply troubled by the continuing large number of executions, including of political prisoners and juveniles," it said, repeating a UN call for a death penalty moratorium and a ban on executing youths.
It said Iran had not kept President Hassan Rouhani's promise to "extend protection to all religious groups and to amend legislation that discriminates against minority groups".
"The above-mentioned commitments have not ... been translated into results," the report said. "Individuals seeking greater recognition for their cultural and linguistic rights risk facing harsh penalties, including capital punishment."
Tehran also continued a crackdown on freedom of expression, having blocked 5 million websites and jailed journalists. A professional ban on human rights lawyers and harassment of activists were "a setback for the country as a whole", it said.
Suspects were allegedly tortured, ill-treated, held for months in solitary confinement with no access to a lawyer and risked the death penalty for crimes such as "corruption on earth" and "enmity against God".
The report said Iran was cooperating more on UN human rights treaties and had invited UN High Commissioner Zeid Ra'ad Al-Hussein to visit. But it had not invited the UN investigator on Iranian human rights, and 24 of 29 UN inquiries on specific cases had gone unanswered.
Two-thirds of women reportedly suffer domestic violence, the report said. Girls are forced to marry young, with about 48,450 between the age of 10 and 14 married in 2011, and at least 1,537 under 10 were married in 2012, the report said.