Israeli defense officials say they have identified an unlikely new threat to national security _ Facebook.

A new list of rules announced Thursday aims to prevent soldiers and Defense Ministry employees from revealing classified information on social networking sites.

The officials say some soldiers have uploaded pictures of themselves with classified equipment, inadvertently revealing sensitive information.

The rules allow soldiers to create pages on networking sites as long as they do not identify themselves as soldiers or reveal any information about what they do.

They spoke on condition of anonymity because the rules have not been officially published.