OTTAWA (AFP) - Canada's spy agency and federal police quietly cooperated with Syrian military intelligence in the post-9/11 torture of three Canadians, documents revealed by public broadcaster CBC showed Monday.

The three men were arrested by Syrian military intelligence during trips abroad from 2001 to 2004, suspected of Al-Qaeda links.

Each claimed upon return to Canada that he had been tortured, and that Canadian security officials had supplied their captors with intelligence and questions to pose to the detainees.

All three men have also claimed their innocence.

According to heavily redacted files obtained by CBC, it all started with a post-9/11 emergency meeting of the top brass of the Royal Canadian Mounted Police (RCMP) and the Canadian Security Intelligence Service (CSIS) to discuss terror threats.

At the top of a list of suspects was Abdullah Almalki, a Syrian-born electrical engineer who ran an electronics exporting business. He was targeted because he had spent time in Afghanistan working for a charity linked to Ahmed Said Khadr - a known associate of Osama bin Laden.

Michel Cabana, who was in charge of covert surveillance and is now RCMP deputy chief, described Almalki in a memo as "a procurement officer for Bin Laden" and Al Qaeda.

Although a case officer said he found nothing overtly suspicious about Almalki "other than the fact that he is an arab running around", documents showed Canada shared its concerns with Damascus.

Cabana wrote that "it would be prudent... to begin the planning for a potential interview of Almalki by Syrian officials based on questions derived from the (RCMP task force)." Canada's ambassador to Damascus at the time, Franco Pillarella, arranged for questions to be hand-delivered to Syrian agents.

Almalki told the CBC he falsely confessed under duress to belonging to Al-Qaeda and being the "left-hand man of Osama bin Laden." This was relayed back to the RCMP.

Ahmad Elmaati, a truck driver, also came under scrutiny because he spent time in Afghanistan and because in 2001 US border officials found a map of nuclear and disease-control buildings in Ottawa.

His supporters have said it was a delivery map.

The documents showed that the RCMP worried that consular officials had discovered his 2001 arrest in Syria and might reveal the RCMP's covert surveillance.

Two months later Elmaati was flown to Egypt where the torture continued for three more years.

In the case of Muayyed Nureddin, a principal at an Islamic school in Toronto, CSIS issued a bulletin to foreign intelligence services requesting his arrest.

A 2008 independent inquiry led by retired Supreme Court judge Frank Iacobucci concluded that Canada's spy agency and federal police force had been "indirectly" responsible for the three men's mistreatment.

A spokesman for Public Safety Minister Ralph Goodale declined to comment on this latest information in the case, citing a multimillion-dollar lawsuit brought by the three men against Ottawa.

Their case is scheduled to go to trial in 2017.

The revelations come after Goodale said Canada continues to use foreign intelligence that may have been derived from the use of torture in some cases, if there is an "imminent security threat".

Although CSIS was ordered to stop doing so in 2009 following a public outcry, the following year a ministerial directive made exceptions for "exceptional circumstances."

Prime Minister Justin Trudeau's Liberal government is reviewing those security protocols.