The Iranians are denying any involvement in the plot, which the RCMP and Canadian intelligence have traced back to al-Qaeda in Iran.
Malizia said they had received "support from al Qaeda elements located in Iran", but added that there was no sign that the conspiracy, which police described as the first known al Qaeda-backed plot on Canadian soil, had been sponsored by the Iranian state.
Nevertheless, Iran reacted angrily. Canada last year severed diplomatic ties over what it said was Iran's support for terrorist groups, as well as its nuclear program and its hostility towards Israel.
"No shred of evidence regarding those who've been arrested and stand accused has been provided," Iranian Foreign Ministry spokesman Ramin Mehmanparast said on Tuesday, according to the Mehr news agency.
He said al Qaeda's beliefs were in no way consistent with the Islamic Republic, and that Iran opposed "any kind of violent action that endangers lives".
"In recent years, Canada's radical government has put in practice a project to harass Iran and it is clear that it has pursued these hostile actions," he added.
Al Qaeda is strongly Sunni Muslim-oriented. Shi'ite Iran did host some senior al Qaeda figures under a form of house arrest in the years following the September 11 attacks, but there has been little to no evidence of joint attempts to stage attacks against the West.
However, a U.S. government source said Iran was home to a little-known network of al Qaeda fixers and "facilitators" based in the Iranian city of Zahedan, very close to Iran's borders with both Pakistan and Afghanistan.
Are we to believe that an oppressive, authoritarian, religiously fanatical government wouldn't be keeping very close ties on a violent, organized, Sunni Muslim terrorist outfit? If only for their own protection, the Iranian Revolutionary Guards would know what AQ was up to.
Iran may be telling the truth - as far as it goes. Might they have known of the plot but had no part in planning it? Given their strained relations with Canada, it is doubtful they would have picked up the phone to let the Canadians know of the danger.