The Anonymous hacking group said Monday it had broken into military contractor Booz Allen Hamilton's network and posted 90,000 military email addresses and passwords online.
Booz Allen isn't commenting. "As part of @BoozAllen security policy, we generally do not comment on specific threats or actions taken against our systems," the company said.
In addition to the email address leak, which Anonymous suggests exposes members of the intelligence community, the group also posted other data it said could potentially offer access to other government agencies and contractors.
"We infiltrated a server on [Booz Allen's] network that basically had no security measures in place," Anonymous said in a posting to the torrent site where it uploaded the data.
The group warned on Sunday that it planned new activity. Via the @anonymouSabu Twitter account, it wrote: "ATTN Intelligence community: Your contractors have failed you. Tomorrow is the beginning." It also said there would be two releases of information on Monday.
Anonymous and another hacking group, LulzSec, have been attacking government and law enforcement targets for a couple of months as part of a campaign they call "Antisec." Anonymous broke into an Arizona police system and released emails from there. It also attacked Turkish government websites.
Authorities in several countries, including Spain, the UK and Turkey, have arrested people they say are affiliated with Anonymous. Briefly prominent hacker group LulzSec has disbanded following member arrests. It had attacked networks of the US Central Intelligence Agency, the US Senate and the UK's Serious Organised Crime Agency.