This Saturday marks the first anniversary of Iran's contested presidential election, which sparked the biggest popular uprising since the 1979 Islamic revolution. One Tehran resident managed to send us a video in which she tells us that the green movement is preparing to take to the streets en masse, despite fears of a brutal response from the authorities.

The poll on 12 June 2009, resulting in the re-election of President Mahmoud Ahmadinejad, was followed by widespread claims of vote-rigging. The ensuing protests, which stretched throughout the year and prompted a brutal crackdown by police, saw thousands of people arrested and dozens killed.

Ahmadinejad warned opposition supporters on Friday that protesters would be "banished by the people". On Tuesday, Supreme Leader Ayatollah Khamenei endorsed the threat and told Iranians to "be watchful" of demonstrators.

Maral, a 34-year-old painter from Tehran, sent us this webcam video on Tuesday. She says that as a non-authorised protest, participants have no guarantee of security.

We will be following events on Saturday via our Observers in the country. If you are in Iran and interested in contributing by sending photos and/or videos and/or speaking to us over the phone (anonymity ensured), then please send us an email at