Photographers say they left Iran as their lives were in danger after June election.
Iran’s human rights record has been criticised in a new report by Amnesty International.
The report highlights what it describes as exceptionally high levels of violence, used in the aftermath of June’s disputed presidential election.
It says that human rights violations are as bad as at any time in the past 20 years, and urges the Iranian leadership to ensure a full, independent investigation of all alleged abuses.
The rights group called on Ayatollah Ali Khamenei, Iran’s supreme leader, to allow United Nations human rights experts to visit the country to help carry out an investigation.
Official inquiries to date “seemed to have been more concerned with covering up abuses than getting at the truth”, the report said.
Iran has dismissed previous criticism of its human rights record.
As Al Jazeera’s Anita McNaught reports, some of those abused have had to flee Iran in fear of their safety and seek refuge in Turkey.