Syrian-born Canadian Maher Arar was detained by U.S authorities during a September 2002 stopover in New York, while returning to Canada from a vacation in Tunisia. (Fred Chartrand/Canadian Press)

Syrian-born Canadian Maher Arar has again been denied the right to sue the United States over his deportation to Syria, where he was tortured.

During a September 2002 stopover in New York, while returning to Canada from a vacation in Tunisia, Arar was detained by U.S authorities, who were acting on information from Canadian security officials. Based on the erroneous Canadian information that Arar had links to al-Qaeda, the U.S. deported him to Syria, even though he was carrying a Canadian passport.

When Arar returned to Canada more than a year later, he said he had been tortured during his incarceration and accused American officials of sending him to Syria knowing that authorities there use torture.

In New York on Monday, the 2nd U.S. Circuit Court of Appeals ruled 7-4 against Arar. He had asked the court to overturn a decision of the U.S. District Court — Eastern District of New York, which had dismissed his suit against dozens of U.S. government officials, including former attorney-general John Ashcroft and former homeland security secretary Tom Ridge.

In the majority opinion, the court said it denied Arar's appeal because the U.S. Congress has not laid out legislation that specifies how unusual claims such as his can proceed and what remedies exist.

The court ruled that allowing the claim to proceed would "offend the separation of powers and inhibit this country's foreign policy."

Court a 'tool' of executive branch, Arar says

A key to the case was the practice of "extraordinary rendition" —when someone with suspected links to terrorism is sent to another country for detention and interrogation, without charges, trial or court approval.

The court said it was hesitant to "create to a new damages remedy that Congress has not seen fit to authorize."

"Even the probing of these matters entails the risk that other countries will become less willing to co-operate with the United States in sharing intelligence resources to counter terrorism," the appeal court said.

In a statement issued through the New York City-based Center for Constitutional Rights, which represents him, Arar said:

"Unfortunately, this recent decision and decisions taken on other similar cases, prove that the court system in the United States has become more or less a tool that the executive branch can easily manipulate through unfounded allegations and fear mongering."

"If anything, this decision is a loss to all Americans and to the rule of law," Arar said.

Maria LaHood, a senior staff attorney at the centre, said an appeal to the U.S. Supreme Court was likely.

"I can't see letting this decision stand without a fight. It's an outrage," she said.

With files from The Associated Press