Civil unrest gripped the Islamic republic in the wake of the June 12 presidential election that brought a disputed victory to Iranian President Mahmoud Ahmadinejad.
That unrest has evolved into political opposition, with the defeated candidate, Mir Hossein Mousavi, leading a growing opposition movement.
Mousavi supporter and former President Ali Akbar Hashemi Rafsanjani led Friday prayers for the first time since the election, describing the atmosphere in Iraq as "bitter." His opposition counterpart Mohammad Khatami, for his part, called for an independent referendum to consider the outcome of the election.
Shaul Bakhash, an Iranian expert at George Mason University, said the opposition movement has been electrified by the new sentiments for such high-level leaders.
"The reaction (to Rafsanjani's speech) has been quite electric and perhaps unintentionally, he reopened the whole debate," he told the Council on Foreign Relations.
Bakhash added, meanwhile, that the clerical regime in Tehran "panicked" in the midst of the growing support for Mousavi just prior to the vote.
The growing political unrest, however, was discounted by Supreme Leader of Iran Ali Khamenei, who described dissent as a threat to political unity.