Iran takes strike at youth vote

The decision, critics said, forces Iranians to rely on state-run media and other government sources ahead of the June 12 election.

It also appeared to be a direct strike at the youth vote that could pose challenges to Ahmadinejad's reelection bid.

More than half of Iran's population was born after the 1979 Islamic Revolution and young voters make up a huge bloc - which helped former reformist president Mohammad Khatami to back-to-back victories in 1997 and 2001 but failed to rally strongly behind Ahmadinejad's opponent, Akbar Hashemi Rafsanjani, four years ago.

Young voters are now strongly courted by the leading reformist candidate, Mir Hossein Mousavi.

"Every single media outlet that is seen as competition for Ahmadinejad is at risk of being closed," said Shahab Tabatabaei, a top aide for Mousavi. "Placing limits on the competition is the top priority of the government."

Tabatabaei said the Facebook block was "a swift reaction" to a major pro-Mousavi rally Saturday in a Tehran sports stadium that included an appearance by Khatami and many young people waving green banners and scarves - the symbolic color of the Mousavi campaign.

Iranian authorities often block specific websites and blogs considered critical of the Islamic regime, but critics of the latest decision said the loss of Facebook means Iranians must rely on the government for information.

"Facebook is one of the only independent sources that the Iranian youth could use to communicate," said Mohammed Ali Abtahi, a former vice president and now adviser to another proreform candidate, Mahdi Karroubi, a former parliament speaker.