Iran has ordered Canada's ambassador to leave the country, the Canadian foreign minister said late Monday, calling the move unjustifiable. Foreign Affairs Minister Maxime Bernier suggested the expulsion of Ambassador John Mundy, who was recently appointed but has not yet had his credentials accepted, was a tit-for-tat move by the government in Tehran. Canada and Iran have tried to come to an agreement on an exchange of ambassadors for some time. "Unfortunately, we have as yet been unable to accept the candidates Tehran has submitted," Bernier said in a statement. "We believe that the expulsion of our ambassador is an unfortunate and unjustified consequence of this situation. As always, Canada remains prepared to receive an Iranian ambassador provided a suitable candidate is presented," he said. The statement did not explain why the Iranian candidates had been unacceptable to Canada. "Iran has been refusing to let our ambassador present his credentials and thereby fully assume his duties," Foreign Affairs spokesman Shaun Tinkler said. "They've decided to downgrade our relations." Bernier said the Canadian Embassy in Iran now will be headed by the charge d'affaires, the No. 2 diplomat. Both countries will continue to maintain embassies in the respective capitals and conduct normal operations, the release said. The diplomatic slap came one day after the Iranian charge d'affaires expressed frustration that his country's overtures to Canada were being ignored by the Canadian government. Seyed Mahdi Mohebi said in an interview with The Canadian Press that he has twice asked for a resumption of high-level contacts up to the foreign minister level. Calls to the Iranian Embassy were not immediately returned Monday. Relations between the two countries have been frosty since former Canadian ambassador Ken Taylor helped spirit Americans out of the U.S. Embassy in 1980 before they could be taken hostage shortly after the Iranian revolution. Recently, Iran's supreme court ordered a review of the death of Zahra Kazemi, a Canadian photojournalist who died in custody after being arrested while taking photographs outside a Tehran prison in 2003. After her death, a committee appointed by then-Iranian President Mohammad Khatami, a reformist, found that Kazemi, 54, died of a fractured skull and brain hemorrhage caused by a "physical attack." Prosecutors filed charges against a secret agent who interrogated Kazemi while she was in custody, but those charges were later dropped. The more conservative judiciary rejected the presidential finding, saying that Kazemi died in an accidental fall when her blood pressure dropped during a hunger strike. A former Iranian army doctor has said he examined Kazemi and observed injuries that could only have been caused by torture and rape. The doctor later received political asylum in Canada. Mohebi, the Iranian charge d'affaires, said he hoped a resolution of the case would lead to a warming of relations. Canada recalled its ambassador in 2003 to protest how Iran was dealing with the case. "Iran hasn't measured up to our standards for full and normal partnership for some time given their human rights record, the Kazemi case, the nuclear issue," Tinkler said. Iran is embroiled in a standoff with the West over its nuclear program. It has refused demands to halt uranium enrichment, a process that can be used to manufacture fuel for nuclear weapons. Iran insists it needs enrichment technology to produce fuel for atomic reactors that will generate electricity.