Online hacktivist group Anonymous has said that it has stolen some usernames and passwords after breaching the servers of Mac-maker Apple.

The group has also published some usernames and passwords, from www.abs.apple.com, on text-sharing website Pastebin, the same place where another affiliate hacker group LulzSec regular posts information about their activities.

Apple uses abs.apple.com for online surveys. It was shut down temporarily.

Anonymous made the announcement on its Twitter account, warning that Apple could be the next target for hackers, according to a report by Reuters.

The warning by Anonymous assumes significance because last month, Apple introduced iCloud, a set of free new cloud services that work seamlessly with apps on user iPhone, iPad, iPod touch, Mac or PC.

Apple CEO Steve Jobs had said that iCloud keeps users important information and content up to date across all user devices.

"All of this happens automatically and wirelessly, and because it’s integrated into our apps you don’t even need to think about it — it all just works," Jobs had said, when the new offering was launched.

However, Anonymous had a veiled message in the warning as well. The group wrote that they may not attack Apple as they are busy elsewhere.

"Not being so serious, but well … Apple could be target, too. But don’t worry, we are busy elsewhere," Anonymous said.

Apple has not commented on the matter so far.

Last month, LulzSec and Anonymous had announced the "AntiSec" campaign against Internet regulation by governments across the world.

The two most prominent hacker groups in the Web world said that they will work together in their attacks against targets related to government such as banks.

LulzSec had said in a statement, "Our Lulz Lizard battle fleet is now declaring immediate and unremitting war on the freedom-snatching moderators of 2011."