(Vahid Salemi/AP Photo)

For the first time in four years, many Iranians logged on to Facebook and Twitter Monday night without using virtual private networks or any anti-filtering software, according to journalists in Tehran. Other blocked sites reportedly remain unavailable.

Following the election protests in 2009, the Iranian government blocked access to Twitter in a bid to limit reporting from the ground. The Green Movement protests, in response to former President Mahmoud Ahmadinejad's re-election, sparked millions of Iranians to share information and pictures on Twitter. Since then, Iranians have turned to special software to navigate around the block.

There has been no official statement from the Iranian government, and it's not clear whether tonight's access was a technical glitch or whether the change will be permanent.

Just three months after President Hassan Rouhani was elected, pledging greater online access, some Iranian officials have become more active on social media.

President Rouhani's media team tweets regularly from @HassanRouhani and Iran's Foreign Minister Javad Zarif started tweeting earlier this month, and Twitter has already verified his account.

thanks for warm welcome to twitter. hope to be able to #interact & stay in touch.

- Javad Zarif (@JZarif) September 4, 2013

For the time being, at least two Western journalists in Tehran are enjoying the freedom while it lasts.

The New York Times' Tehran bureau chief Thomas Erdbrink tweets:

Okay people the rumors are true, this is my first tweet ever using Iran's state cell phone internet service without VPN!!!

- Thomas Erdbrink (@ThomasErdbrink) September 16, 2013

Hello world, we are tweeting without restrictions from Iran.

- Thomas Erdbrink (@ThomasErdbrink) September 16, 2013

And the Washington Post's Tehran correspondent Jason Rezaian weighs in:

No idea if and how long this will last, but I'm enjoying it for the time being.

- Jason Rezaian (@jrezaian) September 16, 2013