The German government on Monday criticized Iran over the arrest of two opposition politicians, saying the detentions violate fundamental human rights, DPA reported.
"We, and the international community, are convinced that such scare tactics breach fundamental human rights and civil liberties," government spokesman Steffen Seibert said.
Hossein Moussavi and Mehdi Karroubi have been kept incommunicado under house arrest for almost two weeks.
The International Campaign for Human Rights in Iran says it has received reports that the Islamic Revolutionary Guard Corps may be responsible.
The German government called on Tehran to immediately disclose the two men's location and grant them access to legal representation.