TEHRAN, Iran - Iran's decision to block access to Facebook -- less than three weeks before elections -- drew sharp criticism Sunday from a reformist opposition hoping to mobilize the youth vote and unseat President Mahmoud Ahmadinejad.
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 re-election 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 main reformist candidate, Mir Hossein Mousavi, as the possible swing factor.
"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, the leading reformist candidate. "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 colour 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 -- and possibly other websites popular with reformists -- 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 pro-reform candidate, Mahdi Karroubi, a former parliament speaker.
During the last presidential race in 2005, information about rallies and campaign updates were sent by text message. In recent years, political blogs by Iranians in the country and abroad have grown sharply. Newcomers such as Twitter also are gaining in popularity.
Iranian officials did not comment on the reported block, but Facebook criticized the decision.
"We are disappointed to learn of reports that users in Iran may not have access to Facebook, especially at a time when voters are turning to the Internet as a source of information about election candidates and their positions," Elizabeth Linder, a spokeswoman for Facebook, said in an emailed statement following questions from The Associated Press.
"It is always a shame when a country's cultural and political concerns lead to limits being placed on the opportunity for sharing and expression that the Internet provides," she wrote.
Linder said the company generally does not give out details on the number of users in a given country, and could not say how many members Facebook has in Iran.