OTTAWA -- Listing the Islamic Revolutionary Guard Corps as a terrorist entity would undermine efforts by the Trudeau government to properly investigate the Iranian plane crash, says Canada's last ambassador to the country.

The government's immediate priority should be to focus on supporting Canadian families, including repatriating remains of crash victims, and the work of Canadian investigators on the ground, said Dennis Horak, who was Canada's envoy to Iran when the two countries severed diplomatic relations in 2012.

"Introducing additional (terror) listings at this point would be counterproductive," Horak told The Canadian Press on Monday. "The Iranians, for example, could believe the accident investigation team is looking to compile evidence for future legal cases against them."

Horak said the government can turn its attention later to making Iran pay for Canada's losses.

"There will be time to address the need for accountability once these initial stages are done. That effort should be centred in the next stage on securing compensation directly from Iran consistent with Islamic law and tradition. That will take negotiations but is likely the best way to secure some measure of compensation for families," said Horak, who ended his career as Canada's Saudi Arabian envoy and was widely considered to be one of the government's top Middle East analysts.

Horak was responding to fresh demands by Canadian Jewish and Iranian organizations for the government to list the Revolutionary Guards as a terrorist entity following last week's downing of a Ukrainian jetliner in Iran.

David Matas, the senior lawyer for B'nai Brith Canada, said Monday that the terror listing would remove a legal obstacle and enable Canadian victims to sue the Iranian government under the Justice for Victims of Terrorism Act.

It was not a new request, but it could be one path to compensation for the families of those killed when Ukraine International Airlines flight PS752 was shot down by an Iranian missile moments after taking off from Tehran early last Wednesday.

All 176 on board were killed, including 57 Canadians. There were 138 people on the plane who were en route to Canada.

The Canadian Press has independently confirmed at least 86 victims with ties to Canada, many of them students and professors returning after spending the December break visiting relatives in Iran.

Canada has already designated the al-Quds branch of the Revolutionary Guards as a terrorist entity, Matas said, so it should follow through and list the complete organization. The paramilitary Quds Force is largely responsible for the group's operations outside of Iran's borders.

"If a terrorist act is committed by the IRGC, but not the Quds Force, a suit is not possible," Matas said.

Liberal and Conservatives MPs voted in the House of Commons in June 2018 to list the entire Revolutionary Guard, but the government has yet to act.

But Horak said the current terrorism act -- if amended -- might not be the best means for the victims to seek redress from Iran because Canada would have to prove that the downing of the plane was an intentional act of terrorism, which would be difficult.

It not clear how Canadian victims would be able to collect a settlement if they ever succeeded in such a lawsuit because there simply aren't a lot of Iranian assets left to lay claim to, he said.

"As I understand it there are no more assets to seize at this moment," said Horak, because most of the money from the seizure of past Iranian properties has been disbursed.

The Canadian government is entitled to seize Iranian assets in Canada, but it isn't allowed to lay its hands on diplomatic property such as embassy buildings or property.

Matas said the government has seized millions in Iranian assets in the past, including a cultural centre, but added: "It may be that it will be difficult to collect in the future."

Matas said there is more at stake than simply money.

"To a certain extent what we're talking about here is not money, but principle. And the principle is a terrorist, is a terrorist, is a terrorist."

Avideh Motmaen-Far, president of the Council of Iranian Canadians, said the downing of the airliner makes it more pressing for Canada to take further action against the Revolutionary Guard.

"This terrorist action, intentionally or not, executed by the IRGC, (emphasized and confirmed) once more the terrorist nature of this organization that has no respect for civilian lives," she said.

This report by The Canadian Press was first published on Jan. 13, 2020.