Canadian Prime Minister Justin Trudeau has said the 176 people, including 57 Canadians, on board the Ukrainian aircraft shot down by a missile shortly after it took off from Tehran last week would still be alive if tensions in the region had not escalated.

Trudeau has been careful to avoid blaming US President Donald Trump for the deaths which followed in the wake of the US assassination of Qassem Soleimani, Iran's top general.

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"If there was no escalation recently in the region, those Canadians would be right now home with their families," Trudeau said in an interview with Global News Television on Monday. "This is something that happens when you have conflict and the war. Innocents bear the brunt of it."

Some Canadians including a leading corporate leader blame Trump in part for the deaths. Trudeau said he had spoken to Trump.

"I've talked about the tremendous grief and loss that Canadians are feeling and the need for clear answers on how this happened and how we're going to make sure it never happens again," Trudeau said.

Trudeau added that he would have "obviously" liked a warning before Trump ordered Soleimani's killing. Canada has troops in Iraq as part of a NATO training mission.

Trudeau said there is also anger directed at Iran which admitted on Saturday that it had shot down the plane in a "disastrous mistake".

"There is a demand for justice. And that is entirely, entirely to be expected and should be heeded very carefully by the Iranian government," Trudeau said.

Canada experts to help

On Monday UN aviation agency ICAO said in a statement it has accepted Iran's invitation to provide expert advice to support the investigation.



Canada's Transportation Safety Board (TSB) also said on Monday that Iranian officials had invited it to take part in the analysis of the voice and flight data recorders from the aircraft.

TSB Chair Kathy Fox said Iran has invited the agency to take part as an observer for the download and analysis of the "black boxes" wherever and whenever that takes place, and the agency hopes to play a larger role.

Security officers and Red Crescent workers at the crash site of the Ukrainian passenger plane on the outskirts of Tehran last week [Nazanin Tabatabaee/WANA via Reuters]

"We are working very hard to build trust daily in order for us to brought in," Fox said. "Canada's role is evolving. It remains to be seen how far that will go."

Natacha Van Themsche, the director of investigations, said Canadian experts also have been invited to inspect the wreckage and the crash site; an unusual step since the plane was not produced in Canada and the crash did not occur there.

Two Canadian investigators have obtained visas to travel to Iran and a second team with expertise in recorder download and analysis will be sent.

The plane crashed early on Wednesday, hours after Iran launched missile attacks on Iraq in retaliation for Soleimani's death. Most of those who died were Iranians and Iranian-Canadians.

After initially pointing to a technical failure and insisting the armed forces were not to blame, Iranian authorities on Saturday admitted it had accidentally shot the aircraft down as it braced for possible American reprisals.

Van Themsche said the agency also will investigate why Iranian airspace was not closed to civilian traffic given the attacks.

Canada suspended diplomatic relations with Iran in 2012, but Trudeau and Canada's foreign minister have been in touch with their Iranian counterparts since the plane was shot down.

Canada's foreign minister and envoys from other countries whose citizens were on board the plane are scheduled to meet in London on Thursday to share information. Those who died also included people from Ukraine, Sweden, Afghanistan, the United Kingdom and Germany.