Canadian Prime Minister Justin Trudeau says evidence suggests that an Iranian missile shot down the Ukrainian passenger jet that crashed on Wednesday.

"We have intelligence from multiple sources including our allies and our own intelligence," Trudeau told reporters. "The evidence indicates that the plane was shot down by an Iranian surface-to- air missile."

This marks a shift from earlier reports that the crash was caused by mechanical failure.

The prime minister added that the jet may have been downed unintentionally and that talks with Tehran on the subject have been encouraging.

The Ukraine International Airlines Boeing 737-800 was carrying about 180 people, including 63 Canadians. Everyone onboard was killed.

The plane crashed shortly after taking off from Tehran. The incident occurred just hours after Iranian missile attacks on bases hosting US-led coalition forces in neighboring Iraq.

CBS News is reporting that US satellites detected two surface-to-air missile launches shortly before the crash.

"Somebody could have made a mistake," US President Donald Trump said. "Some people say it was mechanical. I personally don't think that's even a question."

Iran denies the plane was shot down. A government official told state media that it was unthinkable that missiles were shot into an area with such heavy air traffic.

Canada has requested Iran to allow its officials into the country to identify victims, take part in the investigation, and provide consular services.

NHK