The Defence Department is advising Canadian soldiers not to post personal photos and information on social networking websites like Facebook, citing security concerns.

The advisory was circulated in a memo obtained by CBC News. It warns soldiers not to appear in uniform in online photos and not to disclose their military connections.

"Al Qaeda operatives are monitoring Facebook and other social networking sites," the memo says.

"This may seem overdramatic … [but] the information can be used to target members for further exploitation. It also opens the door for your families and friends to become potential targets as well."

The Defence Department says it is also concerned with postings of photos and information from the battlefront in Afghanistan.

On Feb. 14, military official Brig.-Gen. Peter Atkinson warned against such battle scene postings.

"The insurgents could use this information to determine their success or their lack of it … and determine better ways to attack us," he told reporters in Ottawa.

Military families are already heeding the Defence Department's advice.

Samie Marchand-Whittle, whose husband is in the Canadian Forces, has closed public access to the Facebook page she maintains for military families.

"It's scary to know that they could find out personal information about our families, our children, where we live," said the Edmonton mother of two. "It is really scary."

But Sunil Ram, an international security and defence analyst, questioned the military's warnings about posting information online.

"What we're really talking about is censorship more than anything else," he said on Monday. "This is the military's attempt to control the imagery of what is actually happening on the ground."