Maher Arar says he was tortured in Damascus

Mr Chretien said it was "unacceptable and deplorable" that Syrian-born Maher Arar should have been deported by the US without any consultation with the Canadian authorities.

Mr Arar was detained in New York in September 2002 as he was changing planes while travelling home from holiday in Tunisia.

The US authorities, who suspected Mr Arar of having connections to Osama Bin Laden's al-Qaeda network, eventually deported him to Syria.

Mr Arar has denied having links with terror groups and said he was repeatedly tortured during his detention in Damascus.

He was released last month.

Tip-off allegations

Mr Chretien told the Canadian parliament in Ottawa that he was demanding an explanation from US Secretary of State Colin Powell.

However, senior US Government officials and Canadian opposition members of parliament say they understand the US did not act alone and was reacting to a tip-off from Canadian security services.

An unnamed US intelligence official quoted by the Associated Press news agency said some of the information that led to Mr Arar's deportation had come from Canadian intelligence.

Mr Chretien ruled out a public inquiry into the case, but asked Washington to reveal the names of any Canadian officials involved in the affair.

The BBC's Lee Carter in Toronto says the case is being treated as a salutary lesson about what can happen to the rights of a Canadian citizen during an anti-terrorist clampdown.