NATO is investigating claims by the hacker group Anonymous that it plundered sensitive data from alliance computers, a NATO official said Friday.
"We are aware that Anonymous has claimed to have hacked us and we have security experts investigating these claims," the official said.
"We strongly condemn any leaks of classified documents, which can potentially endanger the security of NATO allies, armed forces and citizens," the official said on condition of anonymity.
The group posted a message on Twitter this week claiming to have looted about a gigabyte of NATO data and said it was too sensitive to release.
"Yes, we haz (sic) more of your delicious data," the Twitter post read. "You call it war; we laugh at your battleships."
Last month, NATO said it was notified by police dealing with digital crimes that an alliance website was probably breached by hackers.
The e-Bookshop website, a separate service for the public to access alliance publications, did not contain sensitive information.
Explore further: Study shows role of media in sharing life events