OTTAWA — Canadian diplomats received claims of possible abuse of prisoners by Afghan's notorious intelligence service as recently as halfway through last year, federal documents reveal.

Two prisoners at the Kandahar intelligence detention centre came forward in July 2009 to tell a Foreign Affairs officer they'd been roughed up during separate interrogations that month, incidents which federal officials described as possible violations of the transfer arrangement between Ottawa and Kabul.

The allegations came at a time when Canadian officials had stepped up unannounced prison inspections.

Diplomats inspecting Afghanistan's shady prisons have received a number of abuse claims since 2007, but the federal government rarely acknowledges them and has insisted the transfer arrangement is working well.

Earlier in 2009 alarm bells went off in Ottawa and Kandahar after a serving National Directorate of Security official told military commanders that they could "torture" and "beat" prisoners. The response of the Canadian government was to step up inspections.

The latest revelation comes as the Military Police Complaints Commission resumes public hearings Tuesday into complaints by two human rights groups that the army knew -- or should have known -- about possible torture in Afghan jails.

A briefing note prepared for Foreign Affairs Minister Lawrence Cannon says the Canadian military considered suspending the handover of prisoners following the latest allegations, but chose to wait for an investigation by the NDS, the spy service whose officers were accused of perpetuating the abuse.

"There is a concern that these actions, if confirmed, are in contravention of the 2005 Arrangement for the Transfer of Detainees and the 2007 Supplementary Arrangement," says a July 14, 2009, memorandum prepared for Cannon and obtained by The Canadian Press under access to information laws.

The allegation was taken seriously enough for the Privy Council Office, the bureaucratic arm of the Prime Minister's Office, to become involved and convene a video conference with Canada's ambassador in Kabul.

A spokesman for Foreign Affairs was not immediately available for comment.

There were suggestions local Afghan intelligence officers tried to cover up the alleged abuse and obstruct Canadian questions.

The diplomat who filed the report complained "an NDS officer repeatedly interrupted her private interview with these two detainees," and came into the room to "retrieve non-essential items such as papers, keys and water jugs." That is a flagrant violation of the agreement which governs the hand over of suspected Taliban fighters and assures Canadian officials that they're allowed to question prisoners in private.

Also, one of the prisoners alleged his copy of the transfer arrangement, handed to every detainee and meant to ensure they know their rights, was taken away by a guard and tossed out.

The note described both incidents as "acts of violence."

The first prisoner claimed that he was grabbed by the throat during his interrogation and verbally threatened, says the briefing document.

"The DFAIT detainee officer observed no visible marks on the detainee's neck," says the report. "The detainee also indicated that the interrogator subsequently apologized for his behaviour, offered him a Pepsi and asked that the detainees 'not tell the Canadians about the incident."'

The second prisoner alleged he was slapped in the face four times and also threatened. As with the first claim, the diplomat saw no marks or bruising.

Officials in Ottawa decided the best course of action was for the ambassador to raise the issue with the head of the NDS, Amrullah Saleh, and ask for an investigation.

It's unclear whether Ottawa considered the allegations to be bona fide cases of abuse. Since 2007 diplomats had received a number of such claims, but lacked the physical evidence, such as injuries or weapons, to verify the claims.

The only case acknowledged by the federal government happened in November 2007 when a diplomat, told by a prisoner about abuse, found implements of torture -- an electric wire and a rubber pipe -- underneath a nearby chair.