OTTAWA–The Department of Foreign Affairs quietly relies on a host of private security contractors to protect Canadian embassies and diplomats across the globe – a small army that needs more supervision, defence experts say.

The call for more oversight follows an incident last month involving the U.S. security firm Blackwater, in which 17 Iraqis died.

Canada has only employed the controversial security contractor to train members of the Canadian Forces and has not used Blackwater for embassy or dignitary protection. However, 2006 federal public account records show a handful of other U.S. and British security firms working in Iraq have separate protection contracts with Canada for work in other countries.

Precisely what kind of service is provided by firms such as Britain's ArmourGroup and subsidiaries of Wackenhut Security Systems, which ran afoul of U.S. lawmakers over private prisons, isn't clear.

There are also questions about a $456,000 contract Canada's former ambassador to Kabul signed last year with Saladin Afghanistan Security Ltd. Documents released under the Access to Information law show the deal, which ran from June 2006 until June 2007, was to provide a quick reaction force to protect the embassy and the army's Strategic Advisor Team – both based in the Afghan capital.

A foreign affairs spokesperson said Friday no one was available to answer questions about security.

Dave Perry, a defence researcher at the Dalhousie University's Centre for Foreign Policy Studies, says the federal government should conduct a review, even though the firms working for Canada may not have gotten into any trouble.

"The issue is: who is providing security and what kind of mechanisms and safeguards are in place to ensure that there aren't any problems," said Perry, who has written about the military's increasing reliance on private companies for logistics support.