A Twitter account associated with the activists' movement claimed credit for the takedown before backtracking and saying it was merely "noting" that the cia.gov site was inaccessible.
The initial statement "#Anonymous takes down main CIA website cia.gov; site is still down | goo.gl/UL2ij" wasfollowed by "We'd remind media that if we report a hack or ddos attack, it doesn't necessarily mean we did it... FYI" from the same YouAnonNews Twitter account a day later.
The conflicting statements have created a certain amount of confusion about who was responsible for the outage.
A CIA representative confirmed problems with the agency's website without commenting on the reasons for the downtime, saying: "We are aware of the problems accessing our Web site, and are working to resolve them."
The cia.gov site returned to normal operation on Saturday. The site (which essentially serves as an online brochure for the spy agency and an outlet for public relations material) has been the target of hacktivists in the past, including a June 2011 attack by LulzSec.
Other elements of Anonymous launched attacks against the Mexican Senate and Interior Ministry websites, in a protest against proposed Mexican anti-piracy laws that hacktivists compared to the SOPA legislation north of the border.
And in a further attack against US law enforcement, other hacktivists posted (partially redacted) information swiped from police and government servers in Alabama.
Hackers claimed they had obtained highly sensitive personal information on 46,000 Alabama residents, including names, Social Security numbers, dates of birth, criminal records, and license plate numbers from insecure state government servers. A censored version of a sample of the hacked data was uploaded to PasteBin.
Anonymous said the hack was in protest against controversial Alabama state immigration