OTTAWA - An Algerian refugee and suspected terrorist detained for nearly four years on a security certificate says his family has been devastated and his reputation destroyed by the ordeal.

Speaking for the first time since a judge loosened his bail conditions, an emotional Mohamed Harkat told a rally Saturday he's innocent but his deportation case will never be resolved without a fair and open trial. That has so far been an elusive goal, he said.

"I spent 43 months in jail without charge and without access to the evidence," Harkat said. "And since June of 2006 I have been like a prisoner in my own home with my wife, who has been a full-time jailer under the toughest (bail) conditions in Canadian history.

"I am mentally exhausted and disgusted with the continued injustice. I feel like an animal on a leash by having a GPS on my ankle. I am angry at the system for allowing such darkness."

Canada's spy agency contends Harkat is an Islamic extremist who came to Canada as a sleeper agent for Osama bin Laden's terrorist network. He was arrested in December 2002 and is one of five men facing deportation under national security certificates.

The former pizza delivery man and gas station attendant says much of the evidence the Canadian Security Intelligence Service has held against him has been destroyed or remains under lock and key, despite new rules allowing special advocates access to his secret files.

Critics say the advocates -- security-cleared lawyers working on behalf of the defence -- are ineffectual and essentially powerless partly because their access to evidence is limited, they cannot scrutinize investigative practices and they can't cross-examine witnesses.

The posts were created by the Conservative government in response to a Supreme Court of Canada ruling that struck down previous rules for deporting alleged terrorists.

Under the new regime, secret evidence can still be heard behind closed doors. But the special advocates are present to protect the rights of the accused and challenge government allegations. Harkat advocate Paul Cavalluzzo has said he's working with one hand tied behind his back because of the restrictions placed upon him in the name of national security.

Michael Bossin of Amnesty International suggested the special advocate system has proven elsewhere to do more harm than good.

"The special advocate system has a veneer of legality," Bossin said. "And that, I think, is one of the worst aspects of it: Because it gives the impression that it is a fair system, it leads to complacency."

He urged vigilance among activists and other Canadians to protect the rights of the accused.

Harkat, who is still subject to strict monitoring, said he fears deportation to his native Algeria, where he says he will be jailed and tortured, and could be killed.

"I will continue to fight until justice prevails," he said, his voice cracking. "I have been persecuted for some things I have never done."

"I have nothing left to lose. I have already lost everything. I'm trying to get my dignity back; I'm trying to clear my name."

Besides the electronic tracking bracelet he wears on his ankle, surveillance cameras keep watch on Harkat's home, his visitors must be pre-approved, his postal mail is intercepted, and the border services agency conducts spot checks.

Saturday's rally was his first public appearance since the March 6 decision by Federal Court Justice Simon Noel giving him more freedom of movement and allowing him to attend political gatherings for the first time since he was granted bail three years ago.

CSIS recently released new details of its case against Harkat, including fresh claims that he had contact with notorious al-Qaida lieutenant Abu Zubaydah.

But defence lawyers say the new material, filed in Federal Court, only underscores their frustration with a legal process that remains largely veiled in secrecy.

CSIS has long contended that Harkat had dealings with Zubaydah, a one-time bin Laden aide captured by U.S. forces and now detained at Guantanamo Bay. CSIS says Harkat also communicated with other terrorist suspects.