The Associated Press
The semi-official Mehr news agency quotes Abdolsamad Khoramabadi, from the board overseeing Internet in Iran, as saying the removal of the blocks was a technical failure that was quickly rectified.
Iranian followers of the networks were disappointed on Tuesday morning when the sites were no longer available, forcing them again to go through proxy servers for access.
Newly elected President Hasan Rouhani has pledged more outreach to the West and a new openness in Iran.
The glitch could point to increasing internal struggles between groups seeking to reopen Facebook and other social networking sites and hard-liners in the establishment, who remain in control of Internet access.
