Hundreds of mourners held a candle-light vigil Thursday night in Toronto to remember 176 people killed when a Ukraine-bound plane crashed in Iran.

Prime Minister Justin Trudeau said multiple intelligence sources indicate that Iran shot down the Ukrainian airliner built by Boeing, although he conceded it may have been unintentional. The dead included 63 Canadians and many others headed for Canada.

At the vigil, people in Toronto -- which has a large Iranian community -- expressed anger and sadness over the tragedy.

"Somebody has to answer us back why this happened. They were innocent people who died," said one of those at the ceremony, Yasmin Roshan, age 43.

Roshan, who came with his nine year old daughter, said he lost two friends in the crash.

He said he blamed US President Donald Trump, who last Friday ordered the killing of a top Iranian general in Iraq, sending tensions between Washington and Tehran soaring.

Candles light up a photo of one of the victims of an airliner crash in Iran that killed 176 people including 63 Canadians
Candles light up a photo of one of the victims of an airliner crash in Iran that killed 176 people including 63 Canadians AFP / Geoff Robins

Iran retaliated Wednesday by firing a barrage of ballistic missiles at Iraqi military bases housing US troops. The airliner went down just hours later.

"They are all gone and we don't know why. It's the right of the community and everybody to know what happened exactly," said a 55-year-old man who gave his name as Sam.

Sam said he was "upset, angry and sad."

In Toronto, an estimated 100,000 Canadians are of Iranian origin. It is one of the largest Iranian communities in North America, after Los Angeles. Officials figures say there were 210,000 Canadians of Iranian origin in 2016.

Some in the crowd at the Toronto vigil shouted "We want justice!"

Vigils were also held in Ottawa and Montreal.

In the capital, Trudeau laid a wreath during a ceremony held outside Parliament.