The CIA's Web site was down Friday afternoon in what looked like a distributed denial-of-service attack publicized by members of the online activist group Anonymous.

With the CIA site inaccessible, the Twitter account for @YourAnonNews tweeted "CIA TANGO DOWN: cia.gov #Anonymous" and included a link to a news story about the outage on Russian site RT.com.

A CIA representative declined to comment on the matter to CBS News beyond offering this statement: "We are looking into these reports."

The site was back online Saturday.

The Anonymous account also posted on Friday a Pastebin link purporting to expose e-mails from the Mexican Mining Chamber, also known as "Camimex." In the Pastebin message, the hackers said they were targeting Camimex for its alleged exploitative labor conditions and business practices.

Earlier on Friday a hacker or group going by the moniker "Casi" took credit for hacking the Web site of the United Nations and released what appeared to be information on vulnerabilities on the site. It was unclear why the UN was targeted. The move did not have the hallmarks of an Anonymous operation, including a clearly written message and the Anonymous motto: "We are Anonymous. We are legion. We do not forgive. We do not forget."

Anonymous has a history of targeting law enforcement and related agencies on Fridays. Last week it released a recording of a conference call between the FBI and U.K. law enforcement that Anonymous snooped on as officials discussed the group and affiliate hackers. It also claimed that day to have hacked into police sites in Texas, Boston, and Salt Lake City, as well as the site of defense lawyers for a U.S. Marine accused of leading a civilian massacre in Iraq, and it claimed to have stolen e-mails. (This hacker chart lists much of Anonymous' activity since last year.)

Updated 2:35 p.m. PT with CIA comment, and Saturday, February 11, 12:22 p.m. PT with information on site being back online.