The group, which has previously claimed responsibility for hacking into , tweeted this afternoon about bringing down the CIA site.

"Tango down - cia.gov - for the lulz," the loosely organized group said in the tweet.

As of late this afternoon, the CIA's main website, at www.cia.gov, appeared to be resolving somewhat slowly or not at all in some cases.

It is not immediately clear if the intrusion resulted in any information being compromised.

The CIA hack adds to what has already been a very busy week for LulzSec. The group this week also for breaking into servers belonging to the U.S. Senate and to game maker Bethesda Software.