Washington and the EU issued a rare joint statement on Iran, warning the country's leaders to live up to their international human rights obligations.
"We are particularly concerned by the potential for further violence and repression during the coming days, especially around the anniversary of the Islamic Republic's founding on 11 February," they said.
The Iranian opposition is expected to revive anti-government protests around the anniversary, raising the prospect of new clashes with the security forces.
Opposition supporters and security forces have clashed repeatedly since President Mahmoud Ahmadinejad won disputed elections in June. Many protesters have been rounded up and put on trial.
"The large-scale detentions and mass trials, the threatened execution of protesters, the intimidation of family members of those detained and the continuing denial to its citizens of the right to peaceful expression are contrary to human rights norms," the EU-U.S. statement said.
"We call on the Government of Iran to live up to its international human rights obligations, to end its abuses against its own people, to hold accountable those who have committed the abuses and to release those who are exercising their rights."
(Reporting by Ross Colvin; editing by Mohammad Zargham)
