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One of two men arrested on charges of plotting an Al Qaeda-linked terror plot to attack a passenger train as it crossed over a bridge in the Toronto area appeared in court Tuesday.

Canadian authorities said Monday Chiheb Esseghaier and Raed Jaser, who live in greater Montreal and Toronto -- were conspiring to carry out an Al Qaeda-supported attack against Via Rail, but posed no immediate threat to the public.

"It was definitely in the planning stage but not imminent," Royal Canadian Mounted Police Chief Superintendent Jennifer Strachan told reporters at a news conference Monday.

Jaser's court appearance in Toronto was brief. He did not enter a plea and was given a new court date of May 23. He had a long beard and wore a black shirt with no tie. He was accompanied by his parents and brother. The court granted a request by his lawyer, John Norris, for a publication ban on future evidence and testimony.

The six-month investigation into the plot, called “Project Smooth,”  was coordinated with the U.S. Department of Homeland Security and the FBI, CBC said.

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    The Royal Canadian Mounted Police said in a statement the operation was coordinated by a multi-agency team comprised of the national police, Canadian Security Intelligence Services, the Canada Border Service Agency and other law enforcement and national security partners in Montreal and Toronto, Canada's two largest cities.

    "This is the first known Al Qaeda planned attack that we've experienced in Canada," Superintendent Doug Best told a news conference.

    The plot is unrelated to the Boston Marathon attack, U.S. Justice Department sources said.

    Charges against the two men include conspiring to carry out an attack and murder people in association with a terrorist group. Police said the men are not Canadian citizens, but they would not comment on where they are originally from.

    Sources tell Fox News that the suspects wanted to have an economic impact and make a big statement.

    The arrests in Montreal and Toronto bolstered allegations by some governments and experts of a relationship of convenience between Iran and Al Qaeda.

    Bruce Riedel, a CIA veteran who is now a Brookings Institution senior fellow, said Al Qaeda has had a clandestine presence in Iran since at least 2001 and that neither the terror group nor Tehran speak openly about it.

    "The Iranian regime kept some of these elements under house arrest," he said in an email to The Associated Press. "Some probably operate covertly. AQ members often transit Iran traveling between hideouts in Pakistan and Iraq."

    U.S. intelligence officials have long tracked limited Al Qaeda activity inside Iran. Remnants of Al Qaeda's so-called management council are still there, though they are usually kept under virtual house arrest by an Iranian regime suspicious of the Sunni-/Salafi-based militant movement. There are also a small number of financiers and facilitators who help move money, and sometimes weapons and people throughout the region from their base in Iran.

    Last fall, the Obama administration offered up to $12 million in rewards for information leading to the capture of two Al Qaeda leaders based in Iran. The U.S. State Department described them as key facilitators in sending extremists to Iraq and Afghanistan. The U.S. Treasury Department also announced financial penalties against one of the men.

    Alireza Miryousefi, spokesman for the Iranian mission to the United Nations, said the terrorist network was not operating in Iran.

    "Iran's position against this group is very clear and well known. (Al Qaeda) has no possibility to do any activity inside Iran or conduct any operation abroad from Iran's territory," Miryousefi said in a statement emailed to the AP late Monday. "We reject strongly and categorically any connection to this story."

    Canada's Public Safety Minister Vic Toews said the arrests show that terrorism continues to be a real threat to Canada.

    "Canada will not tolerate terrorist activity and we will not be used as a safe haven for terrorists or those who support terrorist activity," Toews said in the House of Commons.

    U.S. Rep. Peter King, a New York Republican, said in a statement praising Canadian authorities for the arrests, that the attack was intended "to cause significant loss of human life including New Yorkers."

    Muhammad Robert Heft, who runs an outreach organization for Islamic converts, and Hussein Hamdani, a lawyer and longtime advocate in the Muslim community, said one of the suspects is Tunisian and the other is from the United Arab Emirates. Heft and Hamdani were part of a group of Muslim community leaders who were briefed by the RCMP ahead of Monday's announcement.

    Authorities were tipped off by members of the Muslim community, Best said. Hamdani said the police said they were very thankful to Muslim community leaders for that.

    "It was sort of a thank you moment," Hamdani said. "This tip, this lead, came from the Muslim community. But for the Muslim community we would not be talking about an arrest today. This is evidence and proof that the Canadian Muslim community, rather than a community that should be seen as suspect, is in fact partners for peace and here is the proof of it."

    Hamdani said he did not know if anybody in the room for the briefing knew the suspects. He called the Al Qaeda connection to the Shiite theocracy of Iran "very strange.

    He noted that police said Al Qaeda didn't provide material support and that it was more guidance.

    "What does that mean exactly?" Hamdani wondered. "It could be words of support or inspiration. It could be `Here's the idea I think you should use it."'

    The Canadian Council on American-Islamic Relations, a national Muslim civil liberties organization, planned to hold a news conference in Toronto Tuesday  afternoon to comment on the terror-related  arrests.

    A spokeswoman for the University of Sherbrooke near Montreal said Esseghaier studied there in 2008-2009. More recently, he has been doing doctoral research at the Institut national de la recherche scientifique, a spokeswoman at the training university confirmed.

    Julie Martineau, a spokeswoman at the research institute, said Esseghaier began working at the center just outside Montreal in 2010 and was pursuing a Ph.D. in nanotechnology.

    "We are, of course, very surprised," she said.

    A LinkedIn page showing a man with Esseghaier's name and academic background said he helped author a number of biology research papers, including on HIV and cancer detection. The page says he was a student in Tunisia before moving to Canada in the summer of 2008.

    The page carries a photo of a black flag inscribed with the Muslim declaration of faith: "There is no god but God and Muhammad is his prophet." The same flag was used by Al Qaeda in Irag and then started being used by ultraconservative Islamic groups in Egypt, Tunisia, Mali and elsewhere across the region.

    In Markham, Ontario, north of Toronto, police tape cordoned off half of a duplex, with officers remaining at the scene well into the night. Sanjay Chaudhary, who lives in the other half of the duplex with his family, said the RCMP questioned him about his neighbor Jaser, asking whether he knew him or spoke to him often.

    Chaudhary said he didn't know his neighbor or the woman he believes is the man's wife but added "every day, we see them going out."

    Monday's raid on the house stunned Chaudhary, who said the neighborhood is otherwise "peaceful."

    The arrests came just a few months after two Canadians were discovered among militants killed in a terrorist siege at a gas plant in Algeria. At least 38 hostages and 29 militants were killed in the siege, including Ali Medlej and Xristos Katsiroubas, two high school friends from London, Ontario.

    In 2006, Canadian police foiled the so-called Toronto 18 home grown plot to set off bombs outside Toronto's Stock Exchange, a building housing Canada's spy agency and a military base. The goal was to scare Canada into removing its troops from Afghanistan. The arrests made international headlines and heightened fears in a country where many people thought they were relatively immune from terrorist strikes.

    Fox News' Mike Levine and The Associated Press contributed to this report.