Although mystery still surrounds Mousavi's departure from the capital (and that of fellow reformist leader Mehdi Karroubi), the former presidential candidate was able to post a comment on his website in which he said, "I am not unwilling to become a martyr like those who made that sacrifice after the election for their rightful national and religious demands". In his statement, he insisted that the government must acknowledge "the existence of a serious crisis in the country" as well as release political prisoners, change the electoral law and recognise the right of people to demonstrate.
As he did at the start of the protest movement in June, Mousavi called for democratic reforms but within the current framework of the Islamic Republic, a system centred on the rule by the country's top religious clerics. Both he and Karroubi, his fellow anti-Ahmadinejad challenger, are part of the regime, Mousavi as a (now former) minister and Karroubi as a member of the ruling Shia clerical establishment.
Now however, people are no longer protesting against election fraud, but are shouting "death to Khamenei", something which neither reformist leaders have ever called for.
For weeks, many people on Twitter and scores of blogs have been posting comments like: "Mousavi, this is the time to act. You must lead us and take the first step" or "When will you really start fighting?"
Anti-government protests broke out in the wake of the controversial presidential election that was held on 12 June and which resulted in the re-election of President Mahmoud Ahmadinejad. The unrest has led to the worst domestic crisis in the 30 years of the Islamic Republic.
Opposition leaders insist that the election was rigged, but the government has rejected all accusations.
The authorities have intensified their repression against the opposition since 27 December, when eight people, including Mousavi's nephew, were killed during protests in Tehran.
Meanwhile, the international community continues to appeal to Ahmadinejad and Iranian authorities to stop the repression. However, with the Iranian president saying that repentance by the opposition will not be enough, few hold out much hope.