Security forces used batons to disperse protesters in Tehran
A well-known Iranian activist in his 70s, Habibullah Payman, tells the BBC's Persian service how he and other peaceful demonstrators were beaten up by security forces in Tehran on 4 November.
Opposition supporters took to the streets in their thousands, on the same day as official rallies were held to mark the 30th anniversary of the seizure of the American embassy in Tehran.
I set off with some family members and some friends to join the crowds in Tehran's Haft-e Tir square area.
There was already a large number of people there, chanting slogans. Suddenly, tear gas was fired. People dispersed and ran away.
I saw security forces starting to beat people up. This was all while people were simply leaving the area.
I, too, was attacked. I was hit several times on my head and face and I started to bleed.
The group around me also received some blows, including one friend who actually fell unconscious for a while.
Then, I saw a security vehicle in the side alley that we and another group of peaceful people were heading towards, as we were trying to leave the area.
The security forces attacked people and I was once again beaten, receiving a few more blows and resulting in more bleeding.
The Green [pro-opposition, reformist] movement took part in this rally because the authorities had allowed them to.
They came in peace and with the usual slogan of supporting peace and asking for freedom. I saw no sign of violence or agitation in the crowd.
They marched, they carried their own symbols, they didn't insult anyone or promote violence. Yet, they were attacked violently.
Why do the security forces need to react like this?