Prime Minister Justin Trudeau says Canada has intelligence that suggests that Ukraine Airlines flight PS752 was shot down by an Iranian missile. Likely by accident.
Iran has since taken responsibility for shooting down the aircraft. It was by accident.
All 176 people aboard were killed, including 63 Canadians.
The plane crashed shortly after takeoff from Tehran on Wednesday.
Trudeau said "we have intelligence from multiple sources, including our allies and our own intelligence. The evidence indicates that the plane was shot down by an Iranian surface-to-air missile. This may well have been unintentional."
Iran has extended an offer to the Transportation Safety Board of Canada to visit the crash site. Arrangements are being made to visit the site.