That was the message posted on Moussavi's page on Facebook, the social networking Web site that has proved to be a key source of information in the absence of international media coverage.
The message urged Moussavi's supporters to "protest" and "not go to work."
"Today you are the media," said one message. "It is your duty to report and keep the hope alive."
Iran's ruling system is "going to the slaughterhouse," a post on the site said.