Trudeau has also complained that Canada "didn't get a heads up" from the US on the raid that killed Soleimani. "Sometimes countries take action without informing their allies," the PM said, adding that he would've "obviously" appreciated a warning.

"We also have questions on procedures, for example, being followed by the military as well why was the airspace not closed considering the tensions and what had happened just hours earlier," Van Themsche said.

TSB Chairwoman Kathy Fox said two investigators are on their way to Tehran on Monday as part of the international team of investigators working under the guidance of Iran's Aircraft Accident Investigation Bureau.

Fox pointed out that there are early signs Canada will be allowed to play a larger than originally expected role in the investigation of the crash. The full scope of Canada's role in the investigation will likely be determined during the meeting, Fox said.

Canada has been invited to observe the crash site, examine the wreckage and participate in the downloading of data from the aircraft's recorder box.

The Ukrainian Embassy in Iran initially blamed last week's plane crash in Tehran on engine failure in an attempt to gain access to the crash site, a Ukrainian security official told Reuters on Monday.

"If we had said straight away that they had shot it down, I am not sure they would have let us go to the wreckage at all," Oleksiy Danylov, secretary of Ukraine's national security and defence council, said.

Danilov said that a senior investigator is set to visit Ukraine in the coming days to establish whether local laboratories are suitable for decoding the black boxes.

The Ukrainian Embassy initially issued a statement pointing to engine failure as the cause of the crash on Wednesday. However, the statement was soon replaced by another one stating that the reasons for the deadly incident remained unknown.

Majidi pointed out that it would not have made rational sense for the Iranian government to be so open to foreign assistance if there was indeed a concerted effort by Tehran to cover up evidence.

"Right now what's coming out seems to indicate that a very small circle of people within the [IRGC] might have known," he said. At the same time, those involved in the incident were "quarantined," and it's unclear when information obtained from those individuals actually reached members of Iranian President Hassan Rouhani's government, according to Majidi.

"They were telling the truth as they knew it at the time," he asserted, speaking of Tehran representatives' repeated denials that an Iranian cruise missile was responsible.

Now, Majidi explained, people are left wondering three things: who knew that an Iranian missile was responsible, why did they hide the information and who instructed the relevant individuals to not share the truth with other members of the Iranian government?

Debriefing a session of Iran's parliament on Sunday, Salami stated that the IRGC has no other purpose or wish "but to be torn into pieces for the sake of the security, welfare and peace of [the Iranian] people."

"I swear on the life of my children... I wish I had been inside that plane and fell down and burned along with those loved ones instead of witnessing this tragic incident."

"The Judiciary should establish a special court, headed by a senior judge and tens of experts, to investigate the plane incident," Rouhani said on Tuesday on the sidelines of a domestic agricultural exhibition in Tehran.

The president said, "Since the moment I realized the incident could have happened due to an unusual reason, I made every effort to reduce the investigation time so that we would know the cause of the crash."

Rouhani further said, "I promise all the families of the victims in Iran and all other countries - as I told their leaders and authorities in phone conversations - that the government will follow the case with all its capacities and power."

"This is not an ordinary case, and the whole world is watching us," he added.

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Student-led demonstrations in Iran may pose an even larger threat to the authorities than the nationwide demonstrations in November over gasoline price hikes, analysts say.

The internal turmoil calmed with the U.S. killing of Major General Qasem Soleimani in a drone strike in Iraq on January 3. Anger over the assassination of the popular general, one of the most powerful men in the country, briefly united Iranians.

But a new wave of anti-government protests, this time spearheaded by angry youth, has exploded to life following the Iranian military's shooting down of a Ukraine International Airlines passenger plane near the capital, Tehran, on January 8 that killed all 176 people on board.

Iranian authorities have been accused of attempting a cover-up after originally denying their involvement in the disaster, only to admit they shot down the plane -- citing human error -- after three days of mounting international uproar.

"While there are issues of accountability bound up with those economic issues, the cover-up of the Ukraine plane crash strikes at the heart of this: can Iranians trust the regime, even the supreme leader, in matters of life and death?" said Scott Lucas, an Iran expert at Birmingham University in Britain and editor of the EA World View website.

'Death To The Dictator'

The student protests began on the evening of January 11 following a vigil held at a university in Tehran for the victims of the downing of the Ukrainian plane. The passengers included many young Iranians who were on their way to Canada, via Ukraine, for studies.

The vigils soon turned into anti-government demonstrations as young Iranians took to the streets and gathered in squares in the capital.

Protesters shouted, "Death to the liars," "You have no shame," and "Death to the dictator," a reference to Supreme Leader Ayatollah Ali Khamenei. Images also showed some protesters ripping up photographs of Soleimani.

© VOA/ screenshotIranian riot police used tear gas on anti-government demonstrators on January 11 in Tehran.

Anti-government protests broke out for a third consecutive day on January 13. Rallies took place at Tehran's Sharif University of Technology and Amir Kabir University, with demonstrators chanting slogans such as "Clerics get lost," according to social-media posts.

Tehran's police chief has denied his officers opened fire, saying officers had been ordered to show "restraint."

Images on social media showed bloodied protesters and blood on the streets. Witnesses have claimed that dozens of protesters have been wounded.

Iranian authorities have come under a storm of criticism from across the divide in Iran. Even conservatives and hard-liners have criticized the government's handling of the disaster, accusing authorities of misleading the public.

In a rare public apology issued on January 12, the head of Iran's powerful Islamic Revolutionary Guards Corps (IRGC), General Hossein Salami, begged for forgiveness. Meanwhile, Khamenei on the same day expressed his "deep sympathy" to the families of the 176 victims and called on the armed forces to "pursue probable shortcomings and guilt in the painful incident."

But their words have done little to quell the outpouring of public anger.

'Fan The Fires'

Lucas said the student demonstrations had been fueled by "anger and a sense of betrayal."

"It remains to be seen if this intersects with the economic concerns that fed November's mass protests," he said. "And it remains to be seen if the regime pursues the same deadly repression that it used two months ago, killing hundreds of people and imprisoning thousands, and risks a further escalation."

Narges Bajoghli, an assistant professor at Johns Hopkins University, said the government's crackdown on the student protesters could make "things worse."

"If they think they can 'contain' anger at what they've done through crackdowns, they're only going to fan the fires," Bajoghli said on Twitter.

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Barr told reporters on Monday that Apple had not "given any substantive assistance" to law enforcement agencies looking to crack into a pair of smartphones owned by the shooter - who left four people dead on a Florida naval base in December - but the company directly countered the AG in a statement.

"We reject the characterization that Apple has not provided substantive assistance in the Pensacola investigation," the tech giant said, adding that it had responded to the FBI's requests for help "promptly, often within hours."

"The queries resulted in many gigabytes of information that we turned over to investigators. In every instance, we responded with all of the information that we had."

Apple previously went head-to-head with the FBI in a lengthy legal battle over a similar phone-cracking case related to the 2016 terrorist attack in San Bernardino, in which the company refused to provide the bureau a backdoor into one of the attacker's phones.

Though Apple still maintains "there is no such thing as a backdoor just for the good guys," the company has become more willing to engage with law enforcement in recent years, announcing in 2018 that it would create a special police "portal" allowing officers to request data.

Despite its attitude on encryption, the company's devices have also been found to contain inadvertent backdoors of a sort, with fears of spying triggered last year after a curious microphone glitch popped up, allowing callers to hear recipients speak before they answered the phone. Last August, it was also revealed that company contractors were granted access to customers' private conversations through Siri, the AI assistant program, a practice Apple says it has since ended.

The company turned heads more recently when it confirmed that it scans all images stored in its cloud service for evidence of "child abuse," prompting some critics to slam the company for violating user privacy.