American authorities must "come clean" with their version of events on the arrest, deportation and torture of Maher Arar, Prime Minister Stephen Harper said yesterday after registering an official protest with the U.S.

Harper called U.S. President George W. Bush by telephone to demand answers on Arar's ordeal and assurances they won't be repeated. After the 15-minute talk, the PM said Bush responded "sympathetically" to his concerns and vowed to deliver an official response after looking into them.

"What I would like to see is obviously the U.S. government come clean with its version of events -- I would hope to acknowledge the deficiencies and the inappropriate conduct that occurred in this case," Harper said. "We want to help the U.S. in the fight against terrorism and we share their concerns about security, but at the same time we need to have the assurance that the rules and the agreements between our two governments will be respected in future."

Arar's lawyer Lorne Waldman called the high-level intervention a "positive sign." He hopes to finally get answers on why Arar's Canadian passport was ignored, why Canadian officials were misled and why Arar's rights under international human-rights laws were breached by the U.S.

"What's really at stake here is not just Maher Arar, it's the safety of all Canadians," Waldman said. "It's important that the U.S. government takes this very seriously."

Arar was arrested in New York in 2002 and sent to Syria where he was tortured.

An official inquiry put much of the blame on the RCMP, which passed on false information to U.S. authorities that Arar was an Islamic extremist.