Canadian Prime Minister Justin Trudeau has claimed there is evidence a Ukraine International Airlines Boeing 737 that crashed near to Tehran was shot down by a  ground-to-air missile. Canada had 63 citizens among the 176 who died when the jet plummeted to the ground,  apparently on fire, and exploded. The incident happened minutes after the 737 heading to Kiev had taken off from Tehran's Imam Khomeini airport and came amid heightened tensions between the US and Iran over the assassination of Iranian commander Qassem Soleimania. READ: More than 170 dead as Boeing 737 crashes in Tehran. Iran had earlier launched missile attacks on two bases in Iraq staffed by US personnel. Trudeau said Canada had intelligence from multiple sources " including our allies and our own intelligence". He would not detail the evidence but said it was enough to allow him to share the suggestion with the Canadian people. "The evidence indicates that the plane was shot down by an Iranian surface-to-air missile,'' Trudeau told a Press conference. "This may well have been unintentional. "This new information reinforces the need for a thorough investigation into this matter. "Canada is working with its allies to ensure that a thorough and credible investigation is conducted to determine the causes of this fatal crash. "As I said yesterday, Canadians have questions and they deserve answers." The Canadian claim comes as US media reported intelligence officials there also raised the possibility of a missile strike and President Donald Trump said he had his suspicions about what happened. "It was flying in a pretty tough neighborhood and somebody could have made a mistake,'' Trump told reporters. "Some people say it was mechanical, I personally don't think that's even a question." CBS News said sources had told it a satellite detected the infrared signature of two missile launches followed by a "blip" of an explosion. Newsweek quoted US officials and an Iraqi source as saying the plane was hit by a Russian-made Tor missile. UK Prime Minister Boris Johnson and Australian Prime Minister Scott Morrison also backed the ground-to-air missile scenario. “I can confirm that we have had similar intelligence as our partners have," Morrison told Sydney radio station 2GB. “This is not a deliberate act as we can determine … it’s a terrible accident.” Iran has denied the claims and dismissed them as "illogical rumors". The head of Iran's Civil Aviation Authority, Ali Abedzadeh, told CNN the plane would have gone into free fall if it was hit by a missile. "It is impossible that a missile hit the Ukranian plane,'' he said. An early report from Iranian investigators said the plane was on fire and tried turning back but its crew did not radio for help. Ukrainian officials said they were considering terrorism, a missile strike and catastrophic engine failure as potential causes for the crash. The Iranians have said they will not send the plane's black boxes to the US to be read and want to keep them in Iran if possible. However, they have said Ukrainian investigators will have access to the recorders and have now urged manufacturer Boeing to send representatives to join the investigation. The US National Transportation Safety Board late Thursday confirmed it had been notified of the accident by the Aircraft Accident Investigation Board of the Civil Aviation Organisation of Iran and had designated an accredited representative to the investigation. "The NTSB continues to monitor the situation surrounding the crash and evaluate its level of participation in the investigation,'' it said, noting it would not speculate on the cause of the tragedy and directing questions to the AAIB.