Three people have now been charged for allegedly taking part in a domestic terrorism plot in Canada.
Canadian authorities seized more than 50 electronic circuit boards designed specifically to remotely detonate improvised explosive devices (IEDs).
A spokesman for the Royal Canadian Mounted Police said investigators also seized what they describe as a vast quantity of terrorist literature and instructional material and schematics.
Two of the men were arrested in Ottawa, and a third in London, Ontario.
All three are accused of being involved in a conspiracy to commit terrorist attacks against specific government buildings and transit systems in Canada.
The police operation, dubbed Project Samosa, began in 2009.
Security agencies decided to move against the group now because one of the suspects was about to leave the country.
The operation also uncovered links in the conspiracy between the three accused to others in Canada, Iran, Afghanistan, Pakistan and Dubai.
Police said one of the suspects in custody had also taken training to construct electronic and explosive devices from a militant group in Afghanistan.
Authorities said more arrests are expected.
