A group of computer hackers claims to have breached NATO security and accessed hordes of restricted material, says an msnbc report.

The group called Anonymous says it would be "irresponsible" to publish most of the material it stole from NATO but that it is sitting on about 1 gigabyte of data, the report says.

Anonymous is a loosely organized group of hackers sympathetic to WikiLeaks, says the report. It has claimed responsibility for attacks against corporate and government websites worldwide.