Canadian Prime Minister Justin Trudeau has formally accused Iran of shooting down the plane that crashed shortly after take off in Tehran Wednesday.

Mr Trudeau said fresh evidence suggested that a surface-to-air missile deployed by Iranian military brought down the flight early Wednesday morning.

“Evidence indicates that the plane was shot down by an Iranian surface-to-air missile,” Mr Trudeau said at a televised press briefing Thursday night. “We have intelligence from multiple sources, including our allies and our own intelligence.”

While admitting that the attack might have been “unintentional,” the Canadian leader insisted that a thorough investigation must be carried out.

The Ukraine International Airlines flight 752 crashed shortly after take off from Imam Khomeini International Airport at about 6:12 a.m. Wednesday, killing all 176 people on board.

Amongst the victims were 63 Canadians. Iranians, Britons, Germans and Ukrainians were amongst the nationals on board.

Iran denied any involvement in the crash, with its media citing unnamed aviation experts as blaming it on a technical difficulties.

READ ALSO: Ukraine releases manifest of all passengers killed in Iran plane crash

The plane came down hours after Iran fired ballistic missiles into two military bases where American soldiers were staying in Iraq. The rockets hit the bases, but no Americans or other nationals were injured.

Still, Iran said it was satisfied by the action, which it said was in retaliation for last Thursday’s killing of Qassem Soleimani, it’s top military general and strategist.