This remarkable series of events comes from change_for_iran, an "Iranian Student" in Tehran. These were originally a series of tweets, but I've collected them here in chronological order for easier reading and more permanent "linkability". These messages were sent starting Saturday, 2009-06-20 at 21:07:27 UTC, and ending at 23:05:41 UTC.
it was a nightmare, I can barely breath & my face is burning, Masood got shot in the arm & Shayan's brother is missing
I don't know where to start with, first they attack our peacful memorial gathering in front of the university with water gun
the university's doors were close, we couldn't run everywhere! & then they start shooting tear gas at us
they were so many! riot police, normal police, intel, IRG, Basij! I managed to scape, but they captured so many people
all routes to Azady square were blocked & if anyone stopped walking or walking slow they hit him/her brutally
there was no safe path, people were walking in cycles between all variety of security forces
I think they made fun of people, don't go here, go this way, not that way & for no apparent reason suddenly attacking random people
we tried our best using all known shortcuts for reaching Azady SQ were mousavi was, but ended up in face to face with IRG
they weren't just the ordinary police or motorcycle riot guard, they were soldiers holding MP5 supported by reinforced military cars
we didn't realize for a moment they started shooting at people, the gun's sound was like a toy gun, not loud & the soliders were smiling
I was going to tell masood they are using fake guns for scaring people! until people started screaming in agony
we were at Nosrat st, and that part of that damned street had no were for covering
we ran as fast as we could in the opposite direction, at the same time basiji bastards started to hit fleeing people
I think I saw 2 or 3 people lying on the ground in blood & IRG started to move them, probably hide them.
I lost masood in the crowd in upper streets of Nosrat the irony was everything was calm there & people overthere shocked by the looks of us
it was the biggest disadvantage for us today, police & basij managed to cut off people and prevent them from gathering
@databox they arrested people with cell phone in hands on sight.
they also attacked & arrested anyone with any green symbols or mousavi's pictures
damned government also armed street thugs & Afghan workers with anti riot shields & wooden or electric batons
most of them wearing in house clothings & I think they were really enjoying attacking people
@databox if you have any idea what's happening here you would never asked that
@neatfires No, I didn't see any
@Scott_Berlin It was very hard getting out of Enghelab area & we also ended up helping people at Valiasr st
@Ammidon I can't breath normally & my stomach hurts, but I'm good, thanks.
@DINESCU from what I saw today, we have a very long road for that to happen
apprently when I was wandering in Laleh Park searching for water Shayan managed to take Masood to a local Doctor
@darpana2 I'm good enough to post here, thanks
for a help please found a good way for countering tear & pepper gas, drinking milk didn't help.
@polasani Basij are everywhere also inside all hospitals, and this is currently a big problem regarding Masood's wound
@JCLemay Yes! smoke, tear and the one people call pepper gas. I don't know what really is that, but it make your skin burn
it looks some people are still out there, I can hear a chopper passing by
thanks everybody for the info & links
it looks state TV showed the conflict live via traffic cams, saying: enemy agents attacking police in Azady street
I have no idea why some people still believe in State TV, a woman told me today you just found a new way for playing around streets