OTTAWA - A "furious" Prime Minister Justin Trudeau demanded Saturday that Iran provide Canada with "full clarity" on the shootdown near Tehran of a Ukrainian airliner that killed all 176 aboard, including dozens of Canadian citizens.

Trudeau said he made the demand in a call with Iran's President Hassan Rouhani, who admitted earlier Saturday that the airliner was mistakenly shot down by Iranian missiles.

At a televised press conference, Trudeau said he told Rouhani the admission was "an important step" but "many 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."

"Iran must take full responsibility," Trudeau said.

The prime minister said he insisted to Rouhani that Canada be allowed to participate in the investigation.

Three members of a Canadian rapid deployment team were on their way to Iran and should be on the ground within hours to support families of the Canadian victims, Trudeau said.

Additional team members -- two transportation investigators and 10 consular representatives who will help with the victims' identification and repatriation -- will follow, he said, adding that the Iranians were working on granting visas.

The two countries have not had diplomatic relations since 2012, complicating their current contacts.

By Ottawa's count, 57 Canadian citizens, many of them dual Iranian nationals, were aboard the Ukraine International Airlines flight when it crashed January 8 shortly after takeoff from Tehran's airport.

In addition to Iranians and Canadians, there were victims from Ukraine, Sweden, Afghanistan and Britain.

After days of delay and amid mounting international pressure, Iran's Revolutionary Guards admitted the plane was mistaken for a cruise missile and was shot down with a short-range missile.

Rouhani said it was an "unforgivable mistake" that resulted from "human error."

The incident came just hours after Iran launched a wave of missiles at bases hosting American forces in Iraq in response to the killing of top Iranian general Qasem Soleimani in a US drone strike. No one died in the missile attacks. -AFP