Canada abruptly closed its embassy in Iran and expelled Iranian diplomats in Ottawa Friday, citing safety concerns in Tehran and the long-standing view that Iran is a significant threat to global peace.

"The Iranian regime has shown blatant disregard for the Vienna Convention and its guarantee of protection for diplomatic personnel," Foreign Affairs Minister John Baird said Friday, formally listing Iran as a state sponsor of terrorism.

"Under the circumstances, Canada can no longer maintain a diplomatic presence in Iran,” he said in a statement. “Our diplomats serve Canada as civilians and their safety is our No. 1 priority."

A senior official told CTV News there was a credible threat to Canadian diplomats in Iran.

Baird said the Iranian regime’s support of Syrian president Bashar Assad, Iran’s refusal to comply with the UN’s resolutions on its nuclear program and its regular threats to Israel make it “among the world’s worst violators of human rights.”

“This was a decision that we took very seriously,” Baird told CTV’s Power Play Friday afternoon in a telephone interview from Russia, where he is attending the Asia-Pacific Economic Co-operation forum with Prime Minister Stephen Harper.

Baird denied that the move was a preemptive response to a planned Israeli attack on Iran, as some observers have speculated.

Israeli Prime Minister Benjamin Netanyahu has repeatedly hinted that he is prepared to authorize an attack on Iran's nuclear facilities if international sanctions and diplomatic measures don’t do the trick.

“We’ve received no notice from any other country…that there is any imminent military action,” Baird said, adding: “Unequivocally no.”

He said Ottawa waited to formally sever ties with Iran until all Canadian diplomats and embassy staff safely left the country. The last members of the group left Iran yesterday, he said.

Iranian diplomats in Ottawa have been instructed to leave within five days.

A note written in Persian and posted on the door of the Iranian embassy in Ottawa read: "Because of the hostile decision by the government of Canada, the embassy of the Islamic Republic of Iran in Ottawa is closed and has no choice but to stop providing any consular services for its dear citizens.”

On Friday, Foreign Affairs and International Trade Canada issued an advisory against all travel to Iran.

“Because of heightened regional tensions, Canadians travellers in Iran will be closely watched by Iranian authorities,” reads a statement on the department’s website. “Iranian irritation at the recent Embassy closure may heighten this scrutiny of Canadians.”

Canadians were warned that using cameras in public places in Iran, travelling beyond well-established tourist areas, and casual interactions with Iranians could lead to an investigation and harassment.

“Canadian travellers may be arbitrarily questioned, arrested and detained for a long period,” the statement reads.

Those seeking services of the Canadian consulate in Iran are being directed to the embassy in Turkey.

Baird’s announcement ‘a bold stroke’

Although Canada's relations with Iran have been strained at times since the 1979 Islamic Revolution, many political observers are questioning Ottawa’s sudden decision to sever diplomatic ties with the country.

“I really can’t see the rationale of this move,” former Canadian ambassador to Iran, Kenneth Taylor, told CTV News Channel Friday.

“It’s a very bold stroke to sever diplomatic relations and close the embassy within five days.”

If, as Baird argues, Iran poses such a big threat, it’s more important to have Canadian officials on the ground who can “size up the situation and report from the spot,” Taylor said.

He added that Iran will either “play this up big or shrug it off.”

According to Iran’s semi-official Fars news agency, a spokesperson for Iran's foreign ministry, Ramin Mehmanparast, called Canada's decision "hasty and extreme" and said that Iran would soon respond.

The NDP called Baird’s decision irresponsible.

"What this is showing the world is that when it comes to engagement and trying to work on these difficult problems that require robust diplomacy, we're just walking away," the party’s foreign affairs critic Paul Dewar said.

"I don't see how this is going to help. It might be good rhetoric but it's not good diplomacy."

Miriam Ziv, Isreal’s ambassador to Canada, told Power Play that Baird’s announcement was “a very welcome move,” since Iran has not responded to condemnations from the international community over its nuclear program and human rights violations.

Asked about a potential military strike against Iran, Ziv said that “all options are on the table,” reiterating the Israeli government’s previous responses to the question.

At this point, Israel is still focused on exerting pressure on Iran by way of international sanctions, which must get tougher, Ziv said.

A history of diplomatic tensions

The Canadian embassy in Iran was also closed in the 1980s for eight years after Canadians spirited American diplomats out of Tehran during the post-revolution hostage crisis.

The two countries eventually returned to normal diplomatic relations with an exchange of ambassadors in 1996.

The relationship chilled again in 2003 after a freelance photographer with dual Canadian-Iranian citizenship was killed while in custody in Iran.

Canada described the death as a state-sanctioned murder and recalled its ambassador.

During a meeting with Russia’s foreign affairs minister on Friday, Baird said he delivered Canada’s condemnation of Iran “in no uncertain terms.”

He also asked Russia to reconsider its support of the Assad regime.

Russia has blocked UN Security Council resolutions that would have sanctioned the Assad regime, which has been trying to put down an 18-month uprising.

With a report from CTV's Ottawa Bureau Chief Robert Fife and files from The Canadian Press