The Central Intelligence Agency is systematically monitoring Twitter, following up to 5 million foreign tweets a day, according to a new report.

The CIA’s Open Source Center reviews and analyzes information widely available to the general public, including Twitter and Facebook, and keeps eyes on everything from blogs to tweets to more traditional media, The Associated Press says in a feature article on the unit.

Analysts monitor information in an array of languages and cross-reference it to existing intelligence, and are often called on to provide information on the mood of a region after a foreign policy event.

For example, the Open Source Center built a picture of the real-time reaction from the Middle East after the killing of Osama bin Laden in May to give the White House an idea of public sentiment.

When President Barack Obama gave a speech addressing Middle Eastern issues a few weeks later, the center monitored negative Arabic and Turkic tweets, denouncing the president as too pro-Israel, and Hebrew tweets criticizing the president for being too pro-Arab.

The center’s analysis ends up in Obama’s daily intelligence briefing in some form almost every day, reports the AP.

The CIA started reviewing social media after watching Twitter’s influence during the 2009 Green Revolution in Iran, when thousands protested the contested results of an election that kept Iranian President Mahmoud Ahmadinejad in office.