Iran will try five people arrested in connection with protests last month, the biggest in the Islamic Republic since the aftermath of the presidential election in June, the official news agency said on Thursday.
The agency, quoting a statement by Tehran's revolutionary court, did not identify the detainees or the date of their trials but the charge of "moharebeh" -- an Islamic term meaning warring against God -- carries the death sentence.
Eight people were killed in clashes between security forces and supporters of opposition leader Mirhossein Mousavi on Ashura, the day of ritual Shi'ite mourning that fell on December 27.
The opposition website Rahesabz said on Wednesday more than 180 people, including 17 journalists, 10 Mousavi aides and some members of the outlawed Baha'i faith, had since been arrested.
Hardline clerics and authorities have called on the judiciary to punish opposition leaders for creating tension in Iran, saying they were "mohareb" (enemies of God).
Intelligence Minister Heydar Moslehi repeated government accusations that foreign elements were behind the protests, the newspaper Etemad said on Thursday.
"According to information obtained by the Intelligence Ministry, both rioters and anti-revolutionary figures have some links with the enemies of the country and the (Islamic) system," Moslehi was quoted as saying.
The Intelligence Ministry said this week several foreigners were among those arrested over the Ashura violence, the most serious unrest since the aftermath of the disputed June 12 election victory of President Mahmoud Ahmadinejad.
"The current political environment is the worst in the past 30 years," Mehdi Karoubi, who was defeated with Mousavi in the vote, said in a meeting with political activists, the Rahesabz website said.
A European diplomat was among those arrested but released because of diplomatic protocols, lawmaker Alaeddin Boroujerdi was quoted as saying by the semi-official Mehr news agency.
"A European diplomat was among those who were detained during the unrest on Ashura Day, but because of the Vienna Convention he was released after 24 hours," he said.
The unrest that erupted after the June vote was the biggest in the Islamic state's 30-year history. Authorities deny opposition allegations that voting was rigged.
The stakes are high because Ahmadinejad has championed a nuclear energy policy that has led the country, a major oil producer, into diplomatic conflict with the West, incurring U.N. sanctions on a stretched economy.
Iran rejects U.S. allegations it plans to develop nuclear weapons, saying its programme is intended to produce electricity.