Police officers guard a courthouse in Brampton, Ontario, a suburb of Toronto, June 3, 2006.  [Reuters]

Seventeen suspects, including 12 adults and five youth, were arrested Friday night on terrorism-related charges in a police raid near Canada's largest city of Toronto.

All the suspects were Canadian residents, and most are Canadiancitizens among teens and 20s, officials said at a news conference on Saturday morning in Mississauga, just west of Toronto.

The news briefing was held by Royal Canadian Mounted Police (RCMP), Canadian Security Intelligence Service officials, and law enforcement officials, including the heads of several Toronto-areapolice forces.

"This group holds a real and serious intent," RCMP Assistant Commissioner Mike McDonnell said.

A spokesman for RCMP said earlier that the arrested "were planning to commit a series of terror attacks against targets herein southern Ontario."

Officials at the news briefing did not say what specific targets the suspects may attack, although McDonell did confirm that Toronto's transit system was not a target.

The charges are related to an explosion plot in Ontario. Three tonnes of ammonium nitrate was found there, and the group joined aterrorism training camp, officials said.

The suspects were part of a terrorist cell, close to carrying out attacks on one or more Canadian targets, local media quoted intelligence sources as saying earlier.

The men have no connection with al Qaeda, but were allegedly inspired by militant Islamic groups, the reports say.