Media outlets report that hundreds of thousands marched through central Tehran on June 15, 2009, protesting the results of a national election they claim was stolen by President Mahmoud Ahmadinejad.
The outpouring in Azadi, or Freedom, Square for reformist leader Mir Hossein Mousavi followed a decision by Iran's most powerful figure for an investigation into the vote-rigging allegations.
The crowd - many wearing the trademark green color of Mousavi's campaign - was more than five miles (nine kilometers) long, and based on previous demonstrations in the square and surrounding streets, its size was estimated to be in the hundreds of thousands.
"I am ready to pay any price to materialize the ideals of you dear people," he said, speaking though a portable loudspeaker. "People feel their wisdom has been insulted. We have to pursue legal channels to regain our trampled rights and stop this last lie, and stand up to fraud and this astonishing charade."
Later, a group of demonstrators with fuel canisters set a small fire at a compound of a volunteer militia linked to Iran's powerful Revolutionary Guard as the crowd dispersed from the square. As some tried to storm the building, people on the roof could be seen firing directly at the demonstrators at the northern edge of the square, away from the heart of the rally.
An Associated Press photographer saw one person fatally shot and at least two others who appeared to be seriously wounded.