Canadian Prime Minister Justin Trudeau cast doubt on Iran's claim that it accidentally shot down a Ukrainian jetliner on Wednesday.

Trudeau said the shoot-down of Ukraine International Airlines Flight PS752 'is one of the issues that we certainly need better answers to,' during a news conference on Saturday.

'I am, of course, outraged and furious,' Trudeau said of the crash, adding that whether the tragedy was an accident or not still needs to be determined.

Asked whether he was confident it was an accident, Trudeau replied: 'This is one of the issues that we certainly need better answers to. And that's why this first step of admission of responsibility is an important one by Iran but there are many other questions like that one that will need clear answers to in the coming days and weeks.'

Canadian Prime Minister Justin Trudeau cast doubt on Iran 's claim that it accidentally shot down a Ukrainian jetliner on Wednesday

Trudeau said the shoot-down of Ukraine International Airlines Flight PS752 'is one of the issues that we certainly need better answers to,' during a news conference on Saturday

Trudeau said the shoot-down of Ukraine International Airlines Flight PS752 (pictured) 'is one of the issues that we certainly need better answers to,' during a news conference on Saturday

Rescue workers search the scene where the Ukrainian plane crashed in after taking off from Tehran's international airport early Wednesday

In total, 176 people, of whom 57 were Canadians, were killed when Iran blasted the flight out of the sky apparently thinking it was an incoming cruise missile.

'Canada and the world still have many questions,' Trudeau said at a news conference in Ottawa. 'Questions that must be answered.'

Trudeau said he contacted Iranian President Hassan Rouhani of Iran to let him know that his country's admission that its own armed forces unintentionally shot down a flight 752 is an important step towards providing answers for families.

However, the prime minister insisted 'more steps must be taken.'

'A full and complete investigation must be conducted,' he said. 'We need full clarity on how such a horrific tragedy could have occurred.'

A missile operator opened fire on the Boeing 737 because his communications jammed, and he thought he had only seconds to take out an incoming cruise missile, a Revolutionary Guards commander has said.

Brigadier General Amirali Hajizadeh, the Guards' aerospace commander, said on Saturday the operator mistook the Ukrainian jetliner for a US cruise missile responding to Iranian ballistic missile attacks, which is why he made the split second decision on whether or not to open fire.

'I wish I had died, and I wouldn't have seen such an incident,' Hajizadeh said somberly at a press conference. He claimed that a 'request had been made to clear the sky from civil flights at that time, but it did not happen due to reservations.'

Trudeau, through a spokesman, issued a statement on Twitter after the Iranian admission, saying the crash was a 'national tragedy' for Canadians.

Trudeau, through a spokesman, issued a statement on Twitter after the Iranian admission, saying the crash was a 'national tragedy' for Canadians

Among the dead were a 23-year-old doctoral student at a California university, who was traveling with her sister and their mother. The family had moved to Canada from Iran about seven years ago.

Sara Sabat, 23, who was enrolled at Alliant International University in San Diego, was visiting family in Iran with her sister and mom when the Boeing 737 went down minutes after take off from Tehran's international airport early Wednesday.

Her sister Saba, 21, and their mother, Shekoufeh Choupannejad, were from Edmonton in Alberta, Canada.

Saba's long-time boyfriend remembered her and Sara as 'best friends'.

Daniel Ghods-Esfahani told the CBC in Edmonton that he was comforted they died with their mom, who was an obstetrician and gynecologist in her 50s.

'Given the tragedy of the situation, I take some comfort from the fact that, in that last moment, the three of them were together,' he told the news outlet.

Sara Sabat, 23, who was enrolled at Alliant International University in San Diego, was among those killed in the crash. She was traveling with her sister and their mother. The family had moved to Canada from Iran about seven years ago.