The UN human rights agency on Tuesday voiced deep concern over the arrest and imprisonment of a number of prominent human rights and political activists, lawyers and journalists in Iran over the past two weeks.
"This appears to reflect a further severe clamp-down on critical voices in the country," Rupert Colville, a spokesman for the United Nations High Commissioner for Human Rights, told reporters in Geneva.
"Lawyers, human rights defenders and independent media make a key contribution in democratic societies and must be allowed to carry out their work without facing intimidation, harassment, arrest and prosecution," he insisted.
Colville mentioned in particular the arrest on September 29 of Mohammad Ali Dadkhah, a human rights lawyer who co-founded the Centre for Human Rights Defenders along with 2003 Nobel Peace Prize laureate Shirin Ebadi.
Dadkhah has begun serving a previous nine-year jail sentence handed to him for his "membership of an association seeking to overthrow the government and propaganda against the system."
"The case against him is widely believed to be linked to his work as a human rights defender," Colville said, also lamenting the arrest last week of the son of Iran's former president Akbar Hashemi Rafsanjani, just two days after authorities jailed Rafsanjani's daughter.
The UN human rights office also voiced concern over the Iranian authorities closure last week of the country's leading moderate newspaper, Shargh, after it published a satirical cartoon seen as insulting war veterans, and arrested its director Mehdi Rahmanian.
The agency also pointed to the arrest last week of President Mahmoud Ahmadinejad's press advisor, Ali Akbar Javanfekr, to serve a six-month prison sentence on previous charges of publishing material offensive to Islamic codes and public morality.
And it expressed concern over charges lobbed against Reuters' Iran bureau chief Parisa Hafezi of spreading lies and propaganda.
According to Iranian media, the international news agency was found guilty of the crime of "propaganda against the regime" for a report mischaracterising female ninja students as assassins.
"The ongoing arrest and detention of media professionals and intimidation of media organisations is deeply worrying, especially given we are now entering the run-up to the June 2013 presidential elections," he said.
"We urge the government of Iran to promptly release all those who have been arrested for peacefully exercising their fundamental rights," he said.