The Supreme Court of Canada is seen in Ottawa, ON Dec 20, 2012. (ANDRE FORGET/QMI Agency)

OTTAWA - The Supreme Court decided Thursday not to hear the cases of three of the ‘Toronto 18’ terrorists who challenged their sentences.

Zakaria Amara, the presumed ringleader of the extremist Muslim group, was sentenced to life in prison with no possibility of parole for 10 years for his part in a plot to bomb Toronto landmarks.

Saad Khalid was originally sentenced 14 years in jail, and his sentence was increased to 20 years by the Court of Appeal.

Saad Gaya saw his original four-and-a-half-year sentence plus 43 and a half months of pre-sentence custody increased to 10 and a half years in jail plus time served.

The men were convicted of terror charges in 2009 after they admitted to hatching a plot to detonate truck bombs near targets such as the Toronto Stock Exchange, the CN Tower, an Ontario military base and the Toronto offices of the Canadian Security Intelligence Service.

The aim was to force Canada to withdraw troops from Afghanistan.