MONTREAL -- Several hundred people gathered on Thursday outside Concordia University to pay their respects to the victims of a plane crash in Iran.

A surface to air missile was the likely cause of the crash, which killed 176 people, Prime Minister Justin Trudeau said on Thursday.

At least six Montrealers were on the plane when it crashed, including newlyweds Sara Mamani and Siavash Ghafouri-Azar, engineers who graduated from Concordia.

People prayed, lit candles and shared stories of those lost; the vigil was organized by the Iranian Students Association of Concordia University, the McGill Iranian Student Association (MISA) and the Engineering and Computer Science Graduate Association.

"We are trying to honour the people who lost their lives in that plane crash. We are trying to show our support to their families, to their friends, tell them they are not alone in this grieving, we are with you, we love you and we miss them as well," said Saman Abolfathi, one of the organizers.

In a note to its members, MISA also extended its condolences to the families of the victims.

"If you know any of these people closely or you have any information about them, specifically those who have been in Montreal or at McGill before, please share your information with us," it added.

Those present said they wanted answers as to why the plane crashed and why a missile may have been fired at it, but the vigil was apolitical, organizers stressed.

"This is soothing for us, to know that we are not alone in this pain," said Negin Eslami, who went to high school with Mamani, one of the newlyweds who died.

"It is devastating and so unfortunate for me and my family; young, newlywed, a couple gone forever. We were very close. My family and relatives are still in total shock," Reza Ghafouri, uncle of Ghafouri-Azar, Mamani's husband, told CTV News.

"I cannot come up with the words to describe my kind, dedicated nephew. He was a very positive and passionate person, from childhood until his soul departed from his body. Rest in peace, my dearest, next to your beloved wife."

A second memorial will be held for Mamani and Ghafouri-Azar on Friday at 4 p.m. in the MIE Faculty Lounge (EV 4th floor) at Concordia University.

McGill University also released a statement Thursday ackowledging that one McGill student and two alumni were killed in the crash, though it would not name the victims.

The McGill flag has been lowered out of respect for the victims, as were the flags outside city hall.