"It came to a point where our concern for the safety and security of the public far outweighed our appetite for collecting evidence," said McDonell, the RCMP deputy commissioner.

The U.S. counterterrorism official added there was no reason to believe the group had U.S. targets in mind, but also no reason to exclude the potential.

Canadian police say there is no evidence the suspect group had ties to al-Qaida, but describe its members as being sympathetic to jihadist ideology. Officials are concerned that many of the 17 suspects were roughly 20 years old and had been radicalized in a short amount of time.

The Ontario Court of Justice released details of the charges faced by the 12 adult men arrested Friday and Saturday. The men are scheduled to appear in court Tuesday for a bail hearing.

Each is charged with one count of participating in a terrorist group.

Three of them ¡ª Fahim Ahmad, 21, Mohammed Dirie, 22, and Yasim Abdi Mohamed, 24 ¡ª also are charged with importing weapons and ammunition for the purpose of terrorist activity.

Nine face charges of receiving training from a terrorist group, while four are charged with providing training. Six also are charged with intending to cause an explosion that could cause serious bodily harm or death.

No information was released on the five young males arrested due to federal privacy laws that protect minors.

Canadian media have reported that the suspects attended a training camp in Washago, a rural community 90 north of Toronto. The National Post quoted unidentified residents in the wooded area as saying they heard machine-gun fire and saw men dressed in camouflage carrying equipment.

The Royal Canadian Mounted Police displayed evidence Saturday that included camouflage uniforms, flashlights, walkie-talkies and detonators, but have refused to confirm whether they were used at a training facility.

Officials announced Saturday that the suspects were arrested after the group acquired three tons of ammonium nitrate, which can be mixed with fuel oil to make a powerful explosive. One-third that amount was used in the deadly bombing of the Oklahoma City federal building in 1995.

The Toronto Star reported that undercover Mounties delivered the substance to the group in a sting operation. The Star, citing unidentified sources, said the suspects actually received a harmless substance.

Some people who know the suspects said they were astonished by the arrests.

But Faheem Bukhari, a director of the Mississauga Muslim Community Center, said Jamal, the oldest suspect, had taken to giving hateful sermons and preaching intolerance to young Muslims at a small storefront mosque in Mississauga, a city near Toronto where six of the suspects lived.

"These youth were very fun-loving guys, soccer-loving guys, and then all of sudden they were not associating with guys they used to," Bukhari told AP, referring to some of the younger suspects.

He said Jamal once told "the audience that the Canadian Forces were going to Afghanistan to rape women."

Canada has about 2,300 soldiers in southern Afghanistan to bolster Afghan reconstruction and combat Taliban militants.

Bukhari's description contrasted with the view of another prayer leader at the mosque, who said while Jamal was "aggressive" in his sermons but never promoted hatred or violence.

"I will say that they were steadfast, religious people. There's no doubt about it. But here we always preach peace and moderation," Qamrul Khanson said Sunday.