Iran's official news agency reported that police warned opposition members against holding protests this week.
The report by IRNA on Monday came days after two opposition leaders suggested they will call their supporters to the streets on Wednesday - the 30th anniversary of the seizure of the US Embassy in Tehran.
The call came at a tense time in Iran.
Thousands of people were arrested in a heavy crackdown this summer that crushed mass protests in support of opposition leader Mir Hossein Mousavi, who claimed the June 12 disputed presidential election was stolen through massive vote fraud. Dozens were killed in the crackdown.
It was the country's worst unrest since the 1979 Islamic Revolution.