More than 1,000 people were arrested in June after Iranian authorities declared incumbent President Mahmoud Ahmadinejad the winner in an election critics said was rigged.
Sunday, an estimated two dozen detainees appeared in Revolutionary Court on charges of trying to overthrow the government, CNN reported. The charges are punishable by death under Iran's Islamic law.
Detainees already tried this month included Seyyed Mohammad Abtahi, a former Iranian vice president; Ian Tajbakhsh, an Iranian-American scholar; and Maziar Bahari, an Iranian-Canadian reporter for Newsweek magazine.
The disputed presidential election has sparked the biggest political crisis in Iran since the 1979 Islamic revolution, in which Mohammad Reza Pahlavi was ousted as the shah of Iran and Ayatollah Ruhollah Khomeini was installed as the country's supreme leader.