Iran accused Canada on Saturday of "hostile behavior" under Israeli and British influence after Ottawa cut diplomatic relations, and it raised the prospect of swift retaliation.
Canada said on Friday that it was closing its embassy in Tehran and gave Iranian diplomats five days to leave the country, branding the Islamic Republic as the "most significant threat to global peace and security".
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Ottawa cited Iran's disputed nuclear work, which Western states see as a disguised effort to develop atomic bombs, its hostility toward Israel and alleged military aid to Syrian President Bashar Assad, who is battling a popular uprising.
Iranian Foreign Ministry spokesman Ramin Mehmanparast said the Canadian move was a "continuation of anti-Iranian policies" by Prime Minister Stephen Harper's Conservative government, which has long had poor relations with Tehran.
"The current government of Canada under the leadership of Mr Stephen Harper is known for extreme policies in the domain of foreign policy," Mehr news agency quoted Mehmanparast as saying.
"The hostile behavior of the current racist government in Canada in reality follows the policies dictated by the Zionists (Israel) and the British."
The Jewish state is Iran's arch-enemy, while Britain expelled Iranian diplomats late last year after radical Iranian protesters sacked its embassy in Tehran.
Alaeddin Boroujerdi, who heads Iran's influential parliamentary committee on national security and foreign policy, said there could be an "immediate and decisive" response to Canada's action, Fars news agency reported.
"It is essential that the foreign ministry respond to this action by Canada on the basis of national interests."
Canadian diplomats already gone
Canada's 10 diplomats in Iran have already left Tehran, the Canadian foreign ministry said on Friday.
Western states led by the United States believe Iran is covertly trying to develop nuclear weapons capability, though Iran states its uranium enrichment work is wholly peaceful, aimed at generating electricity and medical isotopes.
Mehmanparast said the Canadian move was an attempt to nullify Iran's diplomatic success in hosting a summit of Non-Aligned Movement developing countries last month, which he said Canada had tried to scuttle.
He said Canada's anti-Iranian policies included a ban on money transfers for Iranian students studying in Canada and the blocking of the bank accounts of ordinary Iranians as a result of Western sanctions imposed on Iran's banking sector.
There is a large Iranian diaspora in Canada, with more than 120,000 people reporting Iranian ethnic origins.
Ottawa's bilateral relations with Tehran deteriorated markedly in 2003, when Iranian-Canadian photojournalist Zahra Kazemi died in Tehran's Evin prison while in custody.
The closure of Ottawa's Tehran mission is the most significant row between Iran and another country since the ransacking of the UK embassy, which British officials said could not have happened without some level of government consent.
The United States has not had a functioning embassy in Tehran since the 1979-81 hostage crisis, when 52 Americans were held for 444 days.
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