Ramin Jahanbegloo was arrested in Tehran about 10 days ago after returning from a trip to India. He is the head of the office of contemporary studies at the private Cultural Research Bureau in Tehran, and a well-known philosopher and writer in Iran who travels frequently to make contact with the world's top thinkers.
From 1997 to 2001, he taught at the University of Toronto.
News reports out of Tehran on Thursday suggest he was charged with espionage and violating security measures.
Jahanbegloo recently wrote an editorial in Spain's El Pais newspaper contradicting Iranian president Mahmoud Ahmadinejad's view that the Holocaust was a myth.
"No one is free from blame for not knowing what happened in Auschwitz's gas chambers, nor are those who voluntarily close their eyes before the true essence of horror," he wrote.
Iran's minister of culture and Islamic guidance rejected speculation that Jahanbegloo was arrested for any of his recent writings.
"Nobody is being detained in Iran because of expression of ideas," Mohammad Hossein Saffar-Harandi told the state news agency.
"When I heard about his detention, I ordered for his case to be followed in deserving way through legal entities."
Jahanbegloo is being held at Tehran's Evin prison, known for the torture of inmates.
Three years ago, Iranian-Canadian photographer Zahra Kazemi was also accused of spying after taking photos outside the same prison.
She died from head injuries sustained while being interrogated. Canadian demands for justice were ignored.
A spokesperson with Foreign Affairs said Canada's ambassador to Tehran, Gordon Venner, has approached Iranian authorities about the arrest, and officials have also been in contact with the Iranian embassy in Ottawa.
Canada was alerted to the case when fellow academics waiting for Jahanbegloo in Europe became worried about his whereabouts.
Foreign Affairs Minister Peter MacKay said little about the case Thursday.
"For reasons of personal safety and concern for this individual, we do not feel that public commentary at this time would be helpful, and we don't want to endanger his life or his current circumstance," MacKay said.
Liberal MP Michael Ignatieff, a friend of Jahanbegloo, says he was not a political activist or anti-Iranian.
"This is an important case that all Canadians should watch with great concern," said Ignatieff, who is seeking the Liberal leadership.
"I can say with certainty that he's never been engaged in anti-Iranian activities . . . He's a voice of civility in Iran and I urge the Iranian authorities to release him as soon as possible."
A former colleague of Jahanbegloo said Iranian officials are ignoring Jahanbegloo's dual citizenship, particularly since he was travelling on an Iranian passport and has been living in Tehran.
"They have put the Canadian officials in a difficult position, and in that sense it's quite similar to what happened to Zahra Kazemi," said Mohamad Tavakoli, a history professor at the University of Toronto.
Tavakoli describes his friend as a cosmopolitan man of letters who acted as an interlocutor between Western intellectuals and Iranian society. He is the author of 20 books that are extremely popular in his native land.
In Toronto, he organized an international conference on Iranian modernity in 2001, and developed a regular discussion group on the country. He was last in Canada two years ago to participate in another academic conference.
"He is a mensch of a guy. He is a lovely person, really personable, he cares deeply about teaching," said Tavakoli.
"He developed a great following amongst students at the University of Toronto, and they always talk about him with much passion and care, and everyone is very upset."