Tara Benyamin in Tehran: Surely they would not fire in a mosque

Eyewitness: More gunshots, and in the space of a few seconds, the crowd began running the other way

Yesterday was the anniversary of the death of the legendary martyr Seyyed Beheshti, a prominent Iranian cleric assassinated in a bombing in 1981. His martyrdom is trumpeted annually by the Islamic Republic in a commemoration ceremony open to the public – and as such, fully licensed.

Since last night, emails began circulating urging protesters to gather at the legal venue for the Beheshti event: Qoba Mosque in north Tehran. Surely, we reasoned, the Revolutionary Guard could not dare open fire at a mosque.

The mosque was crowded and hot; a restless buzz filled the air. Girls in green headscarves and chador-clad women with green wristbands murmured Mirhossein Mousavi's name. I perched on a ledge on the balcony, next to a window overlooking the podium in the men's section. Then it came – a roar of cheering from outside. Standing on tiptoe, I looked through the grates beside me: what an overpowering sight! People, hands raised in the "V" sign, as far as the eye could see in both directions down the street.

Not unsurprisingly, the peace was short-lived. We heard shots, then screams. The crowd tried to stand its ground – linking arms and chanting, "No fear, we're all together". More gunshots, and in the space of a few seconds, the crowd began running the other way. Pushed on all sides, I fell under the panicked mass of people. Someone pulled me up and we ducked into an open gate – some kind soul had opened her home as sanctuary.

The sequence is one I'm getting used to: Gather, disperse. March, run. Chant, get hurt. Hide, tremble with others and share your common rage.