Heritage Minister James Moore says the screening of a controversial documentary about Iran's nuclear program will be rescheduled, a day after the event was cancelled due to reported threats to staff at Ottawa's Library and Archives of Canada.

The 70-minute film, titled "Iranium" was to be screened Tuesday night, followed by a talk from Clare Lopez, an intelligence analyst and former CIA agent.

But according to reports the event was cancelled after Library and Archives of Canada staff received threatening calls by phone and email.

Days earlier, the Iranian embassy in Ottawa had sent a letter requesting that the film not be shown.

An unidentified man also dropped off two envelopes and quickly left the building Tuesday afternoon, hours before the event.

Staff apparently called 9-1-1, thinking the incident was suspicious. Police and firefighters surrounded the building but eventually determined the envelopes did not pose a threat.

The event's cancellation prompted an angry response from Moore, who tweeted Tuesday night that Iran's embassy in Ottawa "will not dictate to the Government of Canada which films will or will not be shown in Canada."

By Wednesday morning, he said the Library and Archives of Canada would hold the event at a later date.

"The show will go on," he wrote.

Immigration Minister Jason Kenney similarly expressed his outrage over the incident.

"The cancellation of tonight's screening of Iranium is outrageous," he tweeted Tuesday evening, adding that he hoped the event's organizers would "overcome intimidation."

An Ottawa group called the Free Thinking Film Society has been trying to screen the film.

According to its website, the group promotes documentaries that advocate "the values of limited, democratic government, free market economies, equality of opportunity rather than equality of result, and the dignity of the individual, all underscored by a healthy and patriotic respect for Western culture and traditions."

"Iranium" was produced by the Clarion Fund, a New York-based non-profit organization that makes and distributed documentaries about what it describes as an "urgent threat" posed by radical Islam to American security. It was founded by Raphael Shore, a Canadian-Israeli film producer and rabbi.