Anonymous said it had released a recording of the confidential call and an email listing participants who were discussing action against it and other similar groups.
"We are aware of the video, which relates to an FBI conference call involving a PCeU (Police Central e-crime Unit) representative," London's Metropolitan Police (MPS) said in a statement.
"The matter is being investigated by the FBI. At this stage no operational risks to the MPS have been identified; however, we continue to carry out a full assessment."
Among those discussed on the excerpt posted by Anonymous were a number of British men who have been arrested by the PCeU as part of an international effort to target hacking groups.
Anonymous and fellow group LulzSec have carried out a number of high-profile hacking actions against companies and institutions across the globe including the U.S. Central Intelligence Agency, Britain's Serious Organised Crime Agency, Japan's Sony Corp and Mexican government websites.
(Reporting by Michael Holden; Editing by Kevin Liffey)
Posted by Jason Lomberg, Technical Editor