The United Nations' monitor for human rights in Iran sounded the alarm Tuesday over a rise in arrests of journalists, saying this was part of a pattern of increasing violations as presidential elections loom.
Seventeen journalists were arrested in the space of one week in January, Ahmed Shaheed told reporters.
In addition, some 50 journalists were already behind bars, he said.
"I'm increasingly alarmed about the plight of journalists, bloggers and others who are defenders and practitioners of freedom of expression in Iran," he said.
"They have been charged with communicating with international news organisations or communicating with human rights organisations, both of which should be protected under law rather than being penalised."
Iran's 2009 elections were marked by a crackdown on opposition and Shaheed noted that there had been little effort to offer redress for the victims and hold perpetrators to account.
The media also faced sharpened state pressure in the 2102 parliamentary elections.
"I am concerned that with elections around the corner in June, these actions against journalists do not bode well for the prospects of a free and fair election in the country," he said.
Shaheed, a former foreign minister of the Maldives who is now a human rights academic in Britain, was named the UN's Iran monitor in 2011.
On Monday he presented a report on Iran to the United Nations Human Rights Council.
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He spotlighted repression of freedom of speech and a slew of other abuses, including torture, forced confessions, secret executions and the jailing of members of the political opposition.
He also pointed to violations of the rights of women and of religious and ethnic minorities.
He hammered home the message Tuesday.
"The picture I get is very disturbing. The situation in Iran is continuing to worsen," he said, adding that abuses were not the preserve of particular institutions but appeared etched into the system.
At Monday's Council session Iran launched a verbal attack on Shaheed.
Mohammad Larijani, head of Iran's national human rights body, claimed Shaheed's work was "unhealthy, non-objective and counter-productive", and piloted by Washington and its European allies.
Shaheed rejected that Tuesday.
"I am very transparent in what I report on," he said. "The allegations are false."
Iran has refused to let Shaheed visit the country, and has responded to only a handful of his scores of official requests for information.
He wrote his report by contacting campaigners and victims inside Iran, as well as exiles and human rights groups.
Iran charged that he failed to consider whether the international community was breaching the rights of its people by imposing sanctions due to Tehran's nuclear programme, which the country insists is for peaceful purposes.
"My concern is that the sanctions are having a significant impact on the population, but I cannot assess this without the government's cooperation," Shaheed said.