Microblogging site Twitter was been rendered inaccessible for about an hour Thursday night after being hacked.

The homepage of the site has been replaced by a message claiming the attack on behalf of the “cyber Iranian army,” a group totally unknown. The personal information of users were not affected.

The company explained the information of its domain name server (DNS) [the system that manages website addresses] had been altered. When trying to connect to twitter.com, users were actually redirected to another website. A message on the page announced: “This site has been hacked by the Iranian Cyber Army.”

“USA think they controlling and managing internet by their access, but they don’t, we control and manage internet by our power,” the message continued, according to the BBC.

During the demonstrations that followed the Iranian presidential election and the disputed re-election of President Mahmoud Ahmadinejad, Twitter and other social platforms were used by opponents to communicate with the rest of the world, after the interruption of telephone networks and Internet access.

This is not the first time that the microblogging site is the victim of an attack. Last summer, Twitter had been made inaccessible after a denial of service probably set up by hackers in Eastern Europe.

Microblogging site Twitter was been rendered inaccessible for about an hour Thursday night after being hacked.