The hacker group Lulz Security (LulzSec) has claimed responsibility for the disruption in the services of CIA’s website for a few hours on Wednesday.

The group, which has claimed responsibility for the recent cyber attacks on the networks of Sonypictures.com and InfraGard – and FBI affiliate, posted a message on Twitter, reading, ""Tango down — cia.gov — for the lulz."

CIA spokeswoman Marie Harf said authorities are aware of the reports and working on them.

LulzSec, which calls itself "the world’s leaders in high-quality entertainment at your expense," recently announced a telephone hotline for people to suggest targets for hack attacks.

The group seems to be working to expose vulnerabilities in various security networks.

After the Sony hack, LulzSec had said that they had attacked Sonypictures.com’s "primitive" security network. The hacker group has also warned the NHS of security loopholes in its network.

The group posted a similar statement after the recent hack attack of the US senate.gov website on Monday.

In the stolen files from senate.gov and which were published online at lulzsecurity.com, LulzSec said, "This is a small, just-for-kicks release of some internal data from Senate.gov — is this an act of war, gentlemen?"

"We don’t like the US government very much," the group added. "Their sites aren’t very secure."