Prime Minister Justin Trudeau says he knows Canadians want answers from an investigation into a plane that crashed outside Tehran, killing everyone  on board — including 138 people who were en route to Canada.

The Ukraine International Airlines Boeing 737-800, bound for Kyiv, crashed shortly after taking off from the Iranian capital, killing all 176 people on board, including at least 63 Canadians.

Trudeau says it is too early to speculate, but he knows Canadians have questions about how the crash happened and that they deserve answers.

He says Foreign Affairs Minister Francois-Philippe Champagne will be speaking with the Iranian foreign minister and conveying the need for a thorough investigation into the crash.

The Transportation Safety Board has said it appointed an expert to monitor the progress of the Iranian investigation.

Trudeau says he also spoke with U.S. President Donald Trump along with other allies earlier today, who all offered their sympathies and support.

(Canadian Press)