BBC Iranian affairs analyst Sadeq Saba looks at the key questions in the wake of the country's bitterly contested presidential election result.
How did this crisis begin?
Authorities have made it hard to organise protests
Street protests, which have drawn the largest crowds since the Iranian Revolution in 1979, followed the announcement of the 12 June presidential election result.
The result, after a strong turnout and a campaign that seemed to energise many young voters, was expected to be much closer, and the poll was perhaps expected to go to a second round.
According to the official result Mahmoud Ahmadinejad received 62.6% of the vote, Mir Hossein Mousavi 33.8%, Mohsen Rezai 1.7% and Mehdi Karroubi 0.9%. Turnout was 85% with just under 40 million Iranians voting.
Millions of Iranian simply did not believe the result. The main demand of the protesters has been an annulment of the result and an election re-run.
Iran's Spiritual Leader Ayatollah Ali Khamenei has since insisted there was no election fraud and has demanded an end to the protests.
What next for the protesters?
We are seeing fewer protesters on the streets and the rallies appear to be smaller and more spontaneous. After the recent killings, people are frightened and families are not allowing their young people to attend.
Mir Hossein Mousavi, runner-up in the presidential election, and others are saying that people should be allowed to demonstrate peacefully. But there is no clear leadership to the protest now.
The authorities have made it very hard to organise protests - they have arrested hundreds of people and restricted their ability to communicate. The authorities appear to be taking tighter and tighter control of the situation.
This said, the next key moment or choice for the protesters comes later this week.
Ayatollah Montazeri, a widely respected senior cleric who is often a critic of the government, is calling for three days of mourning for those killed in recent protests. The days of mourning are set for Wednesday, Thursday and Friday.
Political protests associated with mourning have a strong tradition for Shia Muslims. If large numbers of people come out on these days, much could change.
What is going on behind the scenes?
Former President Mohammed Khatami has been unusually outspoken - continuing to question the election result and calling on the authorities to release those arrested recently.
On the other side, a powerful conservative, speaker of the parliament Ali Larijani, has made some comments that I see as conciliatory.
He said on one of the state channels that the number of people questioning the election result was large.
"This group should be respected and one should not mix this big population's account with a small group of rioters," Mr Larijani said.
Also, the arrest of members of the family of Akbar Hashemi Rafsanjani - a former president, a powerful opponent of President Mahmoud Ahmadinejad and key backer of Mr Mousavi's bid for the presidency - was a strong signal that even the most established figures are not invulnerable.
What is the evidence that the election was rigged?
The way the result was announced was very unusual. It came out in blocks of millions of votes, in percentages, rather than being announced province-by-province as in past elections.
And as the blocks of votes came in, the percentages for each candidate changed very, very little. That suggested that Mr Ahmadinejad did equally well in rural and urban areas.
Conversely, it suggested that the other three losing candidates did equally badly in their home regions and provinces.
This overturns all precedents in Iranian politics and there has been no explanation, despite repeated questions, from the authorities.
It is all very suspicious. But it does not necessarily mean there has been widespread electoral fraud.
For example, a group of international pollsters did an independent telephone survey three weeks ago which suggested a two-to-one level of popular support for Mr Ahmadinejad over Mr Mousavi, with the other candidates on less than 2% each.