The Iranian government has blocked new social network Google+, less than two weeks after it was launched.
A source in the Iranian culture ministry accused the US of using Google+ as "a new spy tool on the Web".
The authorities fear that opposition activists and regime opponents within the country will use the new social network, which already has more than 10 million members, to contact members of the exiled Iranian opposition abroad.
Facebook, Twitter and other social networks are also banned in Iran,
although the country supreme leader Ayatollah Ali Khamenei own a pretty active Twitter account, which includes updates on his activity and statements.
Iran has nearly 30 million Internet surfers, while the country's population stands at some 75 million people. Quite a few of them manage to overcome the restrictions by surfing through proxy servers outside the country.
This way, Iranian can access social networks and update their friends on what is happening in the country, while receiving updates from all around the world.
Meanwhile, the Iranian communication ministry has introduced a new filtering system for the Google and Yahoo search engines. Last Monday, access to all blocked websites in Iran was suddenly made available, likely due to the operation of the new system.
According to Iranian website Tabnak, the glitch was fixed several hours later.