A dozen Iranian journalists and bloggers have been arrested and many others are in hiding after authorities took steps to restrict the media, Reporters Without Borders (RSF) said on Wednesday.
The Paris-based press watchdog has set up a hotline for journalists in danger and has been trying to reach Iranian journalists who may be targeted after disputed elections sparked mass protests in Tehran.
"We have lost contact with many of them," RSF secretary general Jean-Francois Julliard said of the journalists.
"We think that they may have sought refuge in the provinces where the situation is calmer or they may have been arrested," he told AFP.
About a dozen journalists have been arrested since violent protests erupted following the announcement of President Mahmoud Ahmadinejad's re-election, according to RSF figures.
The organisation also condemned a decision to ban foreign journalists from attending mass rallies.
"This is absolutely scandalous, but also worrisome, because it suggests a heightening of repression. Clearly the Iranian authorities want the foreign media to leave the country so that it can crack down on the movement away from the world's gaze," said Julliard.