OTTAWA -- In his first press conference since a Ukrainian passenger plane crashed in Iran, killing 63 Canadians and 113 others, Prime Minister Justin Trudeau said Canadians "deserve answers," adding that it's too early to speculate on the cause of the crash.

Trudeau added that 138 people on the flight were scheduled to get connecting flights to Canada. He would not rule out any potential causes of the crash at this early point in the investigation.

"It's dangerous to speculate on possible causes," Trudeau said.

Asked if he can say definitively whether the plane was "shot down," Trudeau said, "I cannot. It is too early to speculate."

"Our focus today is on the many, many families who are grieving, and our focus in the days and weeks to come will be on answering the questions that they have and that, indeed, we all have as to how this happened," said Trudeau.

Transport Minister Marc Garneau, who appeared alongside the prime minister at the press conference, said the satellite data suggested the plane took off in a normal fashion and appeared to be a "very, very standard departure."

"However, we lost contact with it, suggesting that something very unusual happened. But we cannot speculate at this point, there are a number of possibilities," Garneau said.

Political reaction pours in

In a statement released Wednesday morning, Trudeau said he was "shocked and saddened" to hear about the Ukrainian passenger plane crash in Tehran, Iran which killed 176 people including 63 Canadians.

"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,鈥� Trudeau said

"Today, I assure all Canadians that their safety and security is our top priority,"

Trudeau added that Foreign Affairs Minister François-Philippe Champagne has been in touch with the Ukrainian government and is speaking to other international partners.

Champagne sent out a tweet shortly after the crash, calling the crash 鈥渢ragic鈥� and pledging to keep Canadians informed.

Transport Minister Marc Garneau also said he and his team are working with their international counterparts to seek answers on this crash, tweeting that Canada is offering "technical assistance to the upcoming investigation."

The Ukraine International Airlines jet crashed just minutes after taking off from Tehran's main international airport. All passengers and crew members on board the Boeing 737-800 aircraft were killed.

Reaction from politicians has been pouring in all day as Canadians come to terms with the news.

Outgoing Conservative Leader Andrew Scheer took to Twitter to share his condolences with the families and friends of the victims on what he called this "sad day."

NDP Leader Jagmeet Singh also expressed his sadness on Twitter, saying there are "no words."

"These families deserve clear answers, but whatever the cause, this is devastating. Love to their families, friends, and communities and to everyone touched by this tragedy," Singh said in his tweet.

Several Albertans are confirmed to have been killed in the crash. Alberta Premier Jason Kenney said he is "deeply saddened" by the "devastating news."

"Alberta has been enriched by a small but dynamic and highly educated Iranian community. This is a terrible day for them, and I am sure that all Albertans join with me in expressing our condolences to the entire community, which is affected by this disaster," Kenney said .

He also thanked the government for "pressing for an investigation" into the crash.

Ontario Premier Doug Ford also released a statement in the hours after the incident. He said his heart "breaks for the families and loved ones of those who died."

"Our government and all citizens stand with the Iranian community here in Ontario and across Canada in this time of grief," Ford said in the statement.

Ukrainian President Volodymyr Zelenskiy extended his condolences to the victims' families, cutting short a visit to Oman to head back to Kyiv. Eleven Ukrainians were killed in the crash, as well as 82 Iranian, 10 Swedish, four Afghan, three German and three British nationals.

Iranian officials said they suspected the crash was the result of a mechanical failure. While the Ukrainians initially agreed, they later walked back that assessment, saying an official commission will have to determine the cause of the crash.

The crash happened within hours of an Iranian missile attack on two bases in Iraq where American personnel were stationed. The strikes, according to Iran鈥檚 Supreme Leader Ayatollah Ali Khamenei, were in retaliation for the U.S. airstrike in Baghdad, Iraq that killed Iranian Gen. Qassem Soleimani.

Trump held a media availability just hours after the crash to discuss the missile attack, but he did not mention the plane crash that killed 63 Canadians.