After claiming a successful cyber attack against the U.S. Senate's public website, the hacker collective LulzSec has claimed responsibility for a new attack against the CIA.'s website.

LulzSec posted the a tweet on its Twitter page claiming that it had managed to bring down the public side of U.S. Central Intelligence Agency's website.

The Tweet posted read, "Tango down - - for the lulz". A subsequent tweet posted later in the evening elaborated, "Goodnight twitter. The CIA anti-lizards will probably rise from the packet sea while we rest our shining-yet-saturated power field arrays."

The hack happened just after the group opened up a telephone request line for "fans" to suggest potential targets -- the group has not said whether the cyber attack on was done on request.

A CIA representative has since released a statement confirming that it is "looking into" LulzSec's claims.

Despite the fact that the CIA is yet to confirm the authenticity of LulzSec's reported attack the CIA's website was inaccessible at points on Wednesday -- though this could have occurred as a result of too many users trying to log-on at once to check LulzSec's claims for themselves.

The attack adds to LulzSec's growing portfolio of claimed cyber attacks. Already the group has gained public interest and infamy for its high-profile targeting of Sony Corp. after its PlayStation Network outage. It has also claimed responsibility for attacks on Nintendo, Bethesda Softworks, numerous U.S. broadcasters and the U.S. Senate.

Since the phone-line opened the group has targeted eight separate sites with DDoS attacks at the behest of its callers. These sites include that of The Escapist and the online games EVE Online and League of Legends.

LulzSec are yet to release an official statement about the attack or detail its "hacktivist" motivation for it.