A fourth member of an Islamist extremist group known as the "Toronto 18" has pleaded guilty to two charges stemming from a bombing plot, with sentencing arguments to take place on Oct. 20.

Zakaria Amara, 24, entered his guilty pleas in a Brampton courtroom Thursday to charges stemming from a plot to detonate fertilizer bombs in Toronto and at an unnamed Ontario military base. The specific charges are knowingly participating in a terrorist group and intending to cause an explosion for a terrorist group.

Authorities arrested Amara in June 2006.

"My husband is a great father and a great husband. He's not out to get anybody. They were studying, they had normal lives. I don't know what these people have against them," Nada Farooq, Zakaria's wife, told CTV Toronto shortly after his arrest.

The Globe and Mail later found online conversations in which she expressed extremist views of her own.

Crown attorney Ione Jaffe told Justice Bruce Durno that Amara had planned to place bombs in U-Haul trucks and detonate them by remote control.

"It's gonna start kicking ass," Amara said in a wiretapped conversation. "It's going be kicking ass like never before."

Among the targets under consideration were RCMP headquarters, nuclear power plants and Parliament. The goal was to prompt Canada to remove its troops from Afghanistan.

They allege he is a ringleader in the plot. "Who is the leader? I guess I am," Amara told an undercover agent.

He had attempted to buy the chemicals such as ammonium nitrate fertilizer to build the truck bombs. He wanted to include metal chips in the bombs to maximize the injuries to people.

He was also involved in the December 2005 training camp north of Orillia that tried to give basic military training and Islamist indoctrination to its recruits.

Amara had planned to flee to Pakistan, then Afghanistan, after the attacks.

Three other members of the Toronto 18 have no pleaded guilty. One more was convicted following trial. Charges have been stayed or dropped against seven people and six other men still face trial.

Last Friday, a judge sentenced Ali Dirie, 26, to seven years in prison. Dirie had pleaded guilty to taking part in the group. He will serve an additional two years after adjusting for time served.

Saad Khalid, 23, pleaded guilty in May. He had been arrested in a sting operation. He had been unloading what he thought was ammonium nitrate fertilizer -- used in the 1995 Oklahoma City truck bombing, for example -- when arrested with an accomplice.

Khalid was sentenced in early September to 14 years in prison. He was credited with seven years for time already spent in custody.

Saad Gaya, 21, who had been assisting Khalid, has also pleaded guilty. He has yet to be sentenced.

In 2008, a judge found Nishanthan Yogakrishnan, 21, guilty after trying him on charges of participating in and contributing to a terrorist group.

Yogakrishnan had been 17 at the time of the offence, but the judge sentenced him as an adult to 2� years in prison. Yogakrishnan was released in May because of the time he had already spent in custody.

With a report from CTV Toronto's John Musselman and files from The Canadian Press