The lawsuit was filed in a Brooklyn federal court on Thursday and is the latest development in a case that has strained relations between the United States and Canada, raised security and human rights issues and led to a new deportation deal between Ottawa and Washington.
Computer technician Maher Arar was arrested between international flights at Kennedy airport in New York in September 2002. He was interrogated for 13 days and expelled to Jordan and then Syria, where he said he was held for more than 10 months in a "dark, damp hole" and tortured.
US officials accused him of being a member of al-Qaida.
Arar was freed in October 2003 and returned to Canada, but he is barred from the United States. At a news briefing in New York to announce the lawsuit, Arar spoke by speakerphone.
"I believe that the persons who sent me to Syria knew that I would be interrogated under torture there," said Arar, 33, who lives in Ottawa with his wife and two children. He has been
unemployed since his return from Syria after years of working for a high-tech company.
The suit says Arar's deportation
broke US and international law
Arar added that he had "never knowingly associated with terrorists" and that under brutal treatment in Syria, he "falsely confessed to my torturers."
One of his lawyers, Steven Watt, said: "Syria released him as an innocent man and an innocent man he remains today."
In a statement on Thursday, the US Department of Justice headed by Ashcroft said it believed Arar was a member of al-Qaida, the group blamed for the 11 September 2001 plane strikes and other attacks.
The lawsuit named Ashcroft, Homeland Security Department Secretary Tom Ridge, FBI director Robert Mueller and a dozen other officials as defendants. It said Arar's deportation broke US and international laws against torture.
The Justice Department said its information about Arar could not be made public because it was classified.
"In removing Mr Arar, we acted fully within law and applicable international treaties and conventions," it said.
Lawyers for the Centre for Constitutional Rights said the suit was the first to challenge the government's "extraordinary renditions" programmes of keeping foreigners suspected of being a security risk out of the country.
'US wanted Arar tortured'
US Homeland Security Secretary
Tom Ridge is named in the suit
"Federal officials removed Mr Arar to Syria under the programme precisely because Syria could use methods of interrogation to obtain information from Mr Arar that would not be legally or morally acceptable in this country or other democracies," the lawsuit said.
It was filed on Arar's behalf by the Centre, which has been at the forefront of legal challenges to US detention and deportation policy of Muslim men since the 11 September attacks.
Arar requested a court declaration clearing him of any association with terrorist organisations or suspected terrorists. The lawsuit seeks a declaration of the unconstitutionality of his detention and rights violations.
Thirdly, he demanded unspecified monetary damages for economic losses and emotional and physical injuries.
He has also asked for a public inquiry into the role, if any, of the Canadian police and spy agency in the case, which has been a sticky issue for new Prime Minister Paul Martin.