Prime Minister Justin Trudeau said supporting families and conducting a thorough investigation are Canada's main priorities in the coming days following the tragic plane crash that killed 176 people, 57 of them Canadian, on Iranian soil late last night. 

Trudeau held a press conference alongside Defence Minister Harjit Sajjan, Transport Minister Marc Garneau and Chief of Defence Staff Jonathan Vance this afternoon to address the public for the first time since the crash and provide updated information. 

He confirmed that 138 passengers killed in the crash were supposed to connect to Canada in Kiev.

Prime Minister Justin Trudeau says 138 passengers killed in the Iran plane crash were connecting to Canada. https://t.co/ET93WDPqbL pic.twitter.com/Tf6AGCuEEI

— CBC News: The National (@CBCTheNational) January 8, 2020

"While no words will erase your pain, we want you to know an entire country is with you. We share your grief," Trudeau said, addressing the families and loved ones of victims. 

"Canadians have questions and they deserve answers."

Heartbreaking news from Tehran this morning: 176 people, including 63 Canadians, have lost their lives in a tragic plane crash. My thoughts are with all those who are mourning the loss of family members, friends, and loved ones. https://t.co/rSTTbGj0oG

— Justin Trudeau (@JustinTrudeau) January 8, 2020

Trudeau confirmed that the cause of the crash is still entirely unknown, but he ensured Canadians that it will be thoroughly investigated as soon as possible. 

"[They] all had so much potential, so much life ahead of them"

Canadian PM Justin Trudeau pays tribute to the 63 Canadians killed following the crash of a Ukraine-bound flight which went down minutes after taking off from Iranhttps://t.co/7vNbiuE9kx pic.twitter.com/dN7gsQX8wx

— BBC News (World) (@BBCWorld) January 8, 2020

Asked multiple times about the possible causes of the crash, Minister Garneau emphasized that it's important not to speculate until more information is known, and that information from the black box as well as other intelligence is needed before we have any concrete answers. 

"We cannot speculate right now as to the cause of the tragic accident that occurred," he said, adding that information suggests the plane took off in a normal fashion before losing contact.

“On behalf of all Canadians, I want to express my deepest condolences to those who are mourning the loss of a loved one,” said @JustinTrudeau. “While no words will erase your pain, I want you to know that an entire country is with you. We share your grief.” #cdnpoli pic.twitter.com/KlYOl1MHvI

— Power & Politics (@PnPCBC) January 8, 2020

"We do not know the cause. We know that something sudden occurred, but we do not know the cause. It could have multiple reasons. We will have to wait for more information before being able to determine the cause and it's important not to speculate at this point."

Trudeau also specified that the investigation is being led by the Iranians, since the incident happened on their soil.

Canada does not have a diplomatic relationship with Iran and will therefore have to rely on international partners such as Italy, Australia, France and Ukraine for anything from investigation information to the repatriation of bodies. 

"I am confident that we will be able to be part of the investigation," Trudeau said. "We have much to contribute and I am confident that in our engagement, both through our allies and directly, we are going to make sure that we are a substantiative contributor to this investigation."

The flag on the Peace Tower will be flown at half-mast from now until further notice in memory of the victims of the plane crash in Tehran, Iran, on January 8, 2020. #SenCA #PS752 pic.twitter.com/ShvTeVFGBR

— Senate of Canada (@SenateCA) January 8, 2020

When asked by reporters about the tense situation currently unfolding in Iraq, Trudeau maintained that Canada's position is to encourage deescalation in the region while continuing the mission of fighting against Daesh.