OTTAWA — Canada's military secretly armed Afghan civilians hired as security guards at a forward operating base in Afghanistan, federal documents show.

The unidentified "guard force" was also provided with uniforms so they would not be "mistaken for Canadian soldiers or for that matter members of the Afghan National Army," says a briefing note obtained by The Canadian Press under the Access to Information Act.

All Canadian bases in southern Afghanistan have some form of private protection involving paramilitary forces. They often employ local Afghans under the supervision of former Western soldiers.

The handover of surplus C7 rifles -- the Canadian variant on the American M16 -- was approved by the Strategic Joint Staff, the military's senior decision-making body.

"The distribution of weapons to civilian personnel remains problematic in terms of potential for public criticism, especially in the event of misconduct by an Afghan guard using a Canadian weapon," says the censored document from May last year.

But it was deemed an urgent operational requirement.

The force guarding the unidentified base was different from private security firms, which are plentiful in Afghanistan, because "guard force" members are hired directly off the street.

"The individuals were extensively screened," Lt.-Col. Norbert Cyr, an adviser to the joint staff, said in an interview.

The guards free Canadian soldiers to patrol or train Afghan troops.

Full-fledged private security contractors provide their own weapons and training.

The Canadian weapons carried by guard staff "were at the end of their life cycle." The note indicates the weapons were to be disposed of once replacements could be found.

Arming the group was considered a stop-gap until the army found a private security company -- with its own equipment -- to provide what amounts to an extra defensive ring outside the base.

The military insisted that giving guns to locals would not violate Canadian, Afghan or international law.

"Staff have been assured that the (guard force) operates under strict rules of engagement," says the briefing document.

The guards "were screened and trained by Canadians and are under the supervision of Canadians at all times," unlike a private security agency, which operates independently.

The request that Canada provide the weapons was treated gingerly, and the army insisted that certain safeguards be put in place.

That included a provision that the "equipment would be distributed to (guard force) personnel on duty and held" by Canadian authorities when the staff wasn't on duty.

"Guards are not permitted to leave the camp with any weapons," the military assured Foreign Affairs in a July 2008 letter.

The procedure is similar to the way the Canadian army handled the donation of thousands of C7 rifles to the Afghan army, a program nearing completion.

But Afghan soldiers are given extensive firing-range instruction, as well as classes in the laws of war.

Cyr said the field classes occurred for the guard force group but he wasn't able to comment on any classroom instruction.

The secrecy surrounding the program, and the Canadian government's use of private security contractors in general, drew fire from Liberal defence critic Denis Coderre.

"Canadians deserve to know what these guards and contractors are for ... and what rules are in place to prevent a Blackwater," he said. That was a reference to the murder of 14 Iraqis by guards working for the U.S. contractor Blackwater Worldwide.

"The minister has got some explaining to do."

Foreign Affairs says Canada has signed an international accord that aims to have stricter regulation of hired guns, but provided few specifics.