Ali Dirie, 26, listens during his sentencing hearing on Friday in Brampton, Ont., as seen in this court sketch. (Alex Tavshunsky)A convicted member of the "Toronto 18" group that plotted terrorist bomb attacks on Canadian targets will have to stay behind bars for up to two more years.

Ali Dirie, 26, was formally sentenced to seven years in prison. But after allowances for several years he has already spent in custody, he must spend only two more years behind bars —and he can apply for parole after 12 months.

Both Crown and defence lawyers had asked the judge in Brampton, Ont., to give Dirie a seven-year sentence, but they differed on how much credit he should be granted for time served.

In agreeing with the Crown's request for two more years behind bars, Justice Bruce Durno rejected defence arguments that time Dirie spent in isolation should be credited at three to one. He said Dirie was in part responsible for being placed in isolation because of his own misconduct.

4 members of 'Toronto 18' convicted

Dirie admitted that he procured weapons, arranged false travel documents and tried to recruit extremists for a domestic group that planned attacks on targets that included CSIS headquarters in Toronto.

Four people have now been convicted in the plot that made international headlines when police swooped down in June 2006.

Nishanthan Yogakrishnan, 21, was found guilty by a judge in September 2008 of participating in and contributing to a terrorist group.

Saad Khalid, 23, was the first of the group to plead guilty to trying to cause an explosion for a terrorist group. He was handed a 14-year prison sentence for his part in the plot in September, after pleading guilty last May.

On Monday, 21-year-old Saad Gaya pleaded guilty in a Brampton, Ont., court. At the time of his arrest in June 2006, Gaya was a high school honour student.

In the summer of 2006, an investigation involving Canada's spy agency and the RCMP ended with the arrests of 18 people in the Toronto area and the seizure of apparent bomb-making materials.

Seven of the 18 people arrested have since had their charges dropped or stayed.

With files from The Canadian Press