Ottawa: Prime Minister Justin Trudeau says Canada will work with its international partners to thoroughly investigate the cause of the plane crash in Iran that killed 63 Canadians.

Trudeau says Foreign Affairs Minister Francois-Philippe Champagne and Transport Minister Marc Garneau are reaching out to their international counterparts.

“Our government will continue to work closely with its international partners to ensure that this crash is thoroughly investigated, and that Canadians’ questions are answered,” Trudeau said in a statement.

“Today, I assure all Canadians that their safety and security is our top priority. We also join with the other countries who are mourning the loss of citizens.”

Garneau said on Twitter that Canada would offer technical assistance in the crash investigation.

Trudeau is also offering his condolences to the loved ones of those who died.

The Canadians were among the 176 people killed when a Ukrainian passenger plane crashed minutes after takeoff from Tehran’s main airport, Iranian and Ukrainian authorities said Wednesday.

Ukrainian authorities initially said it appeared mechanical failure was to blame, but later walked that back, saying nothing had been ruled out.

The Ukraine International Airlines Boeing 737-800 was en route to Kyiv when it went down in a field, killing all aboard.

Ukraine’s Foreign Minister Vadym Prystaiko said the plane was carrying 63 Canadians, 82 Iranians, 11 Ukrainian passengers and crew, 10 Swedes, four Afghans, three Germans and three Britons.

“This morning, I join Canadians across the country who are shocked and saddened to see reports that a plane crash outside of Tehran, Iran, has claimed the lives of 176 people, including 63 Canadians,” said Trudeau.

“We also join with the other countries who are mourning the loss of citizens.”

The Canadian Press