Internet users in Iran were surprised when Facebook and Twitter suddenly became accessible for the first time in four years this week, but the government says the move wasn't intentional. On Tuesday, officials said a technical glitch is to blame for the apparent reversal of Iran's ban on social media, dispelling speculation that the government may be easing web restrictions under the leadership of President Hassan Rouhani.

Abdolsamad Khoramabadi, secretary of a government agency on web regulation, says the glitch appears to have arisen from one of Iran's internet service providers (ISPs), and that officials are looking into the matter. According to the New York Times, the sites were once again blocked by Tuesday morning.

"We are investigating to see which of these companies has done this."

"The lack of a filter on Facebook last night (Monday) was apparently due to technical problems and the technological committee is investigating this issue," told the Mehr news agency. "We are investigating to see which of these companies has done this."

Social media websites have been banned in Iran since the nationwide demonstrations of 2009, when thousands took to the streets to protest the re-election of President Mahmoud Ahmadinejad. Today, many use virtual private networks (VPNs) to circumvent government firewalls, though the government has made moves to crack down on workaround solutions in the past.

Recent events suggest that Iran may be softening its stance under Rouhani, a moderate cleric who took office last month. Iranian politicians have been playing a more active role on Twitter under the new administration, and Rouhani himself has called for a more liberal approach to governing the web.

"A strong government does not mean a government that interferes and intervenes in all affairs [and] that limits the lives of the people," he told clerics in Tehran in July. But it remains unclear whether the new president will have the power to affect real change, as all policy decisions must still be rubber stamped by Iran's Supreme Leader Ayatollah Ali Khamenei and other senior clerics.