The Mounties have charged three young Ottawa men — including twin brothers — with various terrorism-related offences.
On Monday, the RCMP charged Suliman Mohamed, 21, with participation in the activity of a terrorist group.
Mohamed was also charged with conspiracy to participate in a terrorist activity with two other Ottawa men.
On Friday, 24-year-old twins Ashton Carleton Larmond and Carlos Honor Larmond of Ottawa were charged with various terrorism-related offences.
The RCMP says Carlos was arrested at the Montreal's Pierre Elliott Trudeau Airport as he was intending to travel overseas for terrorist purposes. The Mounties did not say where he was headed.
The Canadian Press has since learned he was bound for India, though it is unclear if that was his final destination.
Ashton, who played pickup hockey on a men's team, was arrested in Ottawa.
Joseph Addelman, a lawyer for the brothers, said Saturday they planned to vigorously dispute the charges. They are due for a second court appearance Feb. 12.
Mohamed was scheduled to appear in court Tuesday morning.
But as of Monday very little was publicly known about what the three were alleged to have done.
The arrests underscore the reality that there are individuals in Canada who have become radicalized to a violent ideology, "and who are willing to act upon it," said Chief Supt. Jennifer Strachan, criminal operations officer for the RCMP in Ontario.
The RCMP thanked Integrated National Security Enforcement Team partners from the Ottawa police service and the Ontario provincial police.
The Mounties said they would not be providing additional details, given that the matter was now before the courts.
The Harper government is contemplating new laws in response to the October 2014 attacks in which two soldiers — one at the National War Memorial, the other in St-Jean-sur-Richelieu, Que. — were killed in broad daylight.
It has also introduced long-promised changes to strengthen the ability of Canada's spy service to probe terror suspects overseas.
Canada and other western nations fear that citizens who go abroad to take part in the Islamic State of Iraq and the Levant's guerrilla-style battles could come home with intent to do harm.
The latest arrests have rekindled discussion about homegrown radicalization.
Young Muslims who took part in federally sponsored forums in four Ontario cities last year came away with some useful information about recognizing signs of extremism, but they were still unsure who to contact or what to do about it, says a federal account of the sessions.
Post-event surveys indicated participants found the meetings in Hamilton, St. Catharines, London and Windsor "engaging and relevant," say the records released under the Access to Information Act.
However, they had little idea of what to do "once they see signs that someone may be going down the path to violent extremism."
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