Justin Trudeau has today blamed the US 'escalation' in the Middle East for the Iranian shoot-down of a passenger jet in an extraordinary swipe at Donald Trump.

Echoing what Iranian officials have said, Trudeau said the dozens of Canadian crash victims would be 'home with their families' but for the tensions started by the US killing of Qassem Soleimani.

The Canadian PM said the international community had to 'manage the tensions in the region that are brought about by US actions'.

After initially denying involvement, Iran admitted on Saturday that it had shot down the jet in error just hours after launching missile attacks on US bases in Iraq.

Tehran said today it had made multiple arrests as president Hassan Rouhani promised to punish those responsible.

Canadian prime minister Justin Trudeau (pictured) has today blamed the US 'escalation' in the Middle East for the Iranian shoot-down of a passenger jet

Trudeau blamed the US killing of Qassem Soleimani for raising tensions in an extraordinary swipe at Donald Trump (pictured early this morning with his wife Melania)

'I think if there were no tensions, if there was no escalation recently in the region, those Canadians would be right now home with their families,' Trudeau said in an interview with Global television.

He added that the international community has been 'very, very clear about needing to have a non-nuclear Iran' but also in 'managing the tensions in the region that are brought about by US actions as well.'

Iran has made similar statements, blaming its blunder which killed 176 people on 'US adventurism' which left both countries' militaries on high alert.

Tehran had fired a missile barrage at US bases on the night of the crash and mistook the passenger jet for a military plane poised to retaliate.

Trump has yet to respond to Trudeau, with whom he has previously clashed.

Last month the US president called him 'two-faced' after Trudeau and other leaders were caught on video appearing to ridicule Trump at a NATO summit near London.

Trudeau said Canada did not receive a heads up before the United States killed Soleimani, and that he 'obviously' would have preferred one.

Trump says Soleimani had plans for an 'imminent' attack on Americans, and the drone attack came days after a US contractor was killed in Iraq.

Iranian president Hassan Rouhani has today called the shoot-down of the Boeing passenger jet an 'unforgivable error' and vowed to punish those responsible.

Rouhani said 'one person cannot be solely responsible for the plane crash' as he vowed a thorough investigation into the disaster.

In a televised speech, he said his government was 'accountable to Iranians and other nations who lost lives' after dozens of Iranian nationals died in the crash.

'For our people it is very important in this incident that whoever was at fault or negligent at any level' faces justice, he said.

'Anyone who should be punished must be punished.

'Iranian armed forces admitting their mistake is a good first step ... We should assure people that it will not happen again.'

Iranian president Hassan Rouhani (pictured today) has today called the shoot-down of the Boeing passenger jet an 'unforgivable error' and vowed to punish those responsible

Ukraine says the pilots were killed immediately when the Iranian missile struck the plane just below the cockpit (the wreckage is pictured at the crash site near Tehran)

An image from the flight tracker website Flightradar24 showing the path of the Ukranian International Airlines jet which crashed just over two minutes after taking off from Tehran

An Iranian judiciary spokesman, Gholamhossein Esmaili, said today that 'some individuals' had been arrested after an 'extensive investigation'. He did not say how many.

UK prime minister Boris Johnson said the shoot-down of the plane was an 'appalling mistake'.

'It is very important that the bodies are repatriated in a dignified way and that the families are allowed to grieve and to have closure,' he said.

'Clearly, as President Rouhani has said, Iran made a terrible mistake. It is good they have apologised. 'The most important thing now is that tensions in the region calm down.'

Tehran's admission that it shot down the jet in error - after days of furious denials - has sparked a wave of public anger and fresh protests against the regime.

The Ukraine International Airlines jet came down near Tehran last Wednesday, just hours after Iran had fired missiles at US bases.

The cause of the crash was initially shrouded in mystery, with Iran insisting repeatedly that the plane had suffered a technical fault.

When Western intelligence came down on the side of a missile strike, Tehran initially dismissed their allegations as 'psychological warfare' and a 'big lie'.

But Iran finally abandoned its denials on Saturday, admitting that the Revolutionary Guards had shot down the Boeing 737 by mistake.

Ukrainian security chief Oleksiy Danilov told the BBC that the missile had hit the plane underneath the cockpit, killing the pilots instantly.

Tehran admitted on Saturday that it accidentally downed the Ukraine International Airlines plane, killing all 176 people on board on Wednesday (pictured: wreckage at the crash site)

Dozens of protesters gathered and chanted slogans at a Tehran university yesterday amid a wave of public anger over the crash and Iran's denials

Bulldozers were operating at the crash site before Ukrainian investigators even arrived - sparking fears of an Iranian cover-up

The death of Qassem Soleimani had initially united Iranians in mourning last week, but Iran's changing story has sparked a resurgence of protests.

Anti-government protests entered a third day yesterday with dozens of demonstrators chanting slogans at a Tehran university.

The capital's police chief claimed yesterday that the security situation in the capital was 'fine' despite the protests, with riot police deployed to face the protesters.

General Hossein Rahimi denied reports that police had shot at protesters and said officers had been ordered to show 'restraint'.

'The police treated the people who had gathered with patience and tolerance,' he said before the latest protests broke out.

Anti-government protests resumed in Tehran at the weekend with pro-regime gunmen accused of opening fire on demonstrators on Sunday.

Riot police armed with water cannon and batons were seen at Amir Kabir, Sharif and Tehran universities as well as Enqelab Square, while there was also a heavy police presence around the iconic Azadi Square.

Anti-government protests in Iran entered a third day yesterday with the initial public solidarity over Qassem Soleimani's death giving way to anger at the regime

Footage released by police in Iran today appeared to show Rob Macaire, pictured left, shortly before he was arrested on Saturday

Government spokesman Ali Rabiei denied a 'cover-up' yesterday despite the days of denials in which Rabiei himself had dismissed claims of a shoot-down as 'psychological warfare'.

Rabiei said all details provided by officials prior to Saturday's admission had been based on the information available to them at the time.

'Some officials were even accused of lying and a cover-up but, in all honesty, that was not the case,' he declared.

'Lying is intentionally and knowingly faking the truth. Lying is covering up. Lying is knowing a fact and not expressing it or twisting the truth.'

A string of Iranian celebrities have also turned on the regime and two state TV hosts have quit over Tehran's three days of false reporting on the crash.

Leading Iranian film director Masoud Kimiai has pulled out of Tehran's annual Fajr Film Festival in protest, saying he was 'on the side of the public'.

A prominent singer, Alireza Assar, has also cancelled a concert in a bid to show support for the protests which resumed over the weekend.

Iran's only female Olympic medallist Kimia Alizadeh has already announced her defection from the Islamic republic, piling further pressure on the regime.

Tehran is now signalling de-escalation in the stand-off with the United States which had sparked fears of a Middle East conflict.