The trouble began when police tried to arrest a teenage member of a notorious drug-dealing gang.

Within hours, the snowy streets of Rinkeby, a northern suburb of the Swedish capital Stockholm, had erupted into violence with his fellow gang members hurling Molotov cocktails at passing vehicles, torching parked cars, throwing rocks and looting shops.

The mob fought with police to free 17-year-old Maikal Hassan, the son of Ethiopian immigrants, and as they advanced, one officer drew his pistol and fired a shot at the gang and missed, while others shot high into the air to try to scare the masked youths.

Trump was reported — incorrectly — as claiming there had been a ‘terrorist incident’ in Sweden

Eventually, police withdrew for their own safety and were forced to call the imam from the local mosque to ask him to appeal to the rioters to disperse. Even then the disturbance continued until the early hours.

The riots on Monday night in Rinkeby, a migrant ghetto known locally as ‘Little Mogadishu’, are a major embarrassment for the Swedish government. They came just two days after Donald Trump, the U.S. President, was widely ridiculed for comments he made at a rally in Florida last weekend.

‘You look at what’s happening last night in Sweden,’ thundered Trump. ‘Sweden? Who’d believe this? Sweden? They took in large numbers [of asylum seekers]. They’re having problems like they never thought possible.’

In fact, he had been referring to a report on Fox News, which blamed an alleged breakdown in law and order in Sweden on an influx of migrants over the past 20 years

Trump was reported — incorrectly — as claiming there had been a ‘terrorist incident’ in Sweden.

In fact, he had been referring to a report on Fox News, which blamed an alleged breakdown in law and order in Sweden on an influx of migrants over the past 20 years.

Trump’s comments drew immediate derision from the Swedish government and pro-migrant groups, which gleefully pointed out that the most interesting item in the Swedish news that day had been a photograph of a live elk trying to mount a wooden elk.

King Carl Gustaf said it is ‘important to present’ good news and that Trump’s allegation was damaging the country’s reputation

The Swedish royal family even joined in. King Carl Gustaf said it is ‘important to present’ good news and that Trump’s allegation was damaging the country’s reputation.

The fact that Sweden, the most liberal of European countries, openly welcomed asylum seekers, refugees and economic migrants over 20 years is not in doubt.

Some 1.7 million have arrived since the Nineties, transforming a country with a population of just ten million.

In the past two years alone — as war in Syria and Afghanistan, and conflict and poverty elsewhere in the Middle East and Africa has fuelled mass migration — Sweden has taken in 275,000 immigrants.

Now, in the wake of Trump’s claims, the riots in Rinkeby this week and reports that some 300 foreign-born Swedes have joined Islamic State, that open-door policy and its consequences are under scrutiny as never before.

Once home to working-class Swedes, Rinkeby’s population is now 90 per cent foreign incomers.

The few Swedes who remain called the place Little Mogadishu not just because of the large population of Somalis, but because — as in the Somali capital — violence and fear are endemic.

Maikal Hassan, the young man whose arrest led to the disturbances, was a member of the ‘Rinkeby Network’ gang that controls much of the local drug dealing.

Hassan — first named in a criminal police report when he was just ten years old; at 15, he was under youth detention for eight counts of assault, robbery and burglary — had been apprehended during a rare foray by officers into what is generally accepted as a no-go zone.

His brother was shot dead in a gangland feud last year.

‘These people don’t want to live a normal European life,’ a Rinkeby resident named Anton told me.

‘It’s a jungle. I never go out after dark and don’t carry much money. It’s too dangerous.’

Now, in the wake of Trump’s claims, the riots in Rinkeby this week and reports that some 300 foreign-born Swedes have joined Islamic State, that open-door policy and its consequences are under scrutiny as never before. Pictured, the Rinkeby riots

As I arrived at Rinkeby underground station this week, I was approached by a group of a dozen or so young foreign men who tried to sell me hard drugs — even though police patrols were less than 100 yards away.

When I ignored them, they turned their backs. I headed away from them towards the shops, many bearing Arabic script, and restaurants offering specialities from Africa and the Middle East.

The gangs here rule by fear — and even warn shopkeepers when they are going to be burgled, telling them they will get back a small cut of the takings as long as they do not raise the alarm. Many feel they have little choice but to comply.

‘The youths come into my shop and threaten me and my staff almost every day,’ said Nouri, 44, an Afghan granted asylum in 1998 who runs a shoe shop close to where the riots broke out.

‘They come in here and grab pairs of expensive shoes and just walk out. There is nothing I can do. If I report them to the police they will torch the store. There are usually about 40 to 50 thugs hanging out here on the square at night.’

One man who knows from bitter experience about the reality of life in Rinkeby is Hanif Azizi, the officer responsible for policing the area. On Monday, as the police faced the rioters, he says he told a colleague: ‘Perhaps Trump was right after all.’

The gangs here rule by fear — and even warn shopkeepers when they are going to be burgled, telling them they will get back a small cut of the takings as long as they do not raise the alarm. Pictured, a burnt-out car in Rinkeby

At his office a mile from the flashpoint, dressed in plain clothes and with a pistol tucked into his belt, he admitted that, regardless of claims by the Swedish government, many areas are firmly in the control of foreign criminal gangs.

‘They are laughing at our society because they can do whatever they want,’ he told me. ‘They use fear and violence to try to stop the police from doing our job. There are so many that you can’t handle them.

‘They have tactics and they are very clever. The people here don’t think they are part of Swedish society. They listen to the imams at the mosque more than they listen to us. These criminals are in control.’

An Iranian immigrant who came to Sweden aged nine, Mr Azizi blamed social ills, lack of officers, 'passive' policing, and sentences being too soft for criminals, and that anyone helping police was more likely to be punished by their community than praised.

‘The good people leave,’ he said.

And Rinkeby is not an isolated example. Immigrant gangs are said to control several other areas of Stockholm. In a recent report, police admitted there are a staggering 53 ‘no-go zones’ in the country where it is unsafe to patrol.

Similar demographic changes due to migration have occurred in the suburbs of other Swedish cities, too, where tension is always simmering.

In Gothenburg, on the west coast, gangs of youngsters, mainly from Morocco, live on the streets having rejected life in care homes to survive on their wits.

One of the city’s biggest shopping malls, Nordstan, has been so plagued by gangs of young thieves it was declared another a ‘no-go’ zone. If caught, the youths, who have no ID documents, claim to be under 16 and escape prosecution.

As I arrived at Rinkeby underground station this week, I was approached by a group of a dozen or so young foreign men who tried to sell me hard drugs — even though police patrols were less than 100 yards away

It must be a wretched life for these youngsters. It has been reported that six Afghan child refugees have committed suicide in Sweden in the past six months as the government attempts to care for 25,000 unaccompanied migrant children.

The authorities stand accused of trying to cover up crimes involving migrants, including alleged sexual assaults committed at a recent music festival, and at New Year celebrations in the capital.

The Swedish National Council for Crime Prevention statistics for 2016 show the number of reported rapes increased by 13 per cent year on year, to 6,560, while the number of reported sexual assaults increased by 20 per cent.

While it is not clear who is to blame for this increase, the National Council’s annual security survey found that immigrants were 2.5 times more likely to commit crimes than Swedish citizens.

Yet, despite this, the Swedish government continues to dismiss allegations that immigration is to blame in part for the rise in crime and civil unrest, saying any problems were due to ‘alienation, unemployment and problems with housing’.

Fredrik Lundh Sammeli, a spokesman for the ruling Social Democratic Party, told me that ‘the troublemakers are a very small group of individuals that has been challenged by the police and our society — but they are not related to immigration’. Whatever the truth, at the very least there has been a massive failure of integration.

And, as in other European countries with rising immigrant populations, this has promoted the rise of Far Right groups.

In Sweden, such groups have been accused of a series of fire bombings of mosques, as well as violent attacks on drug dealers and street children.

Politically, the beneficiary of growing anger about migration and its impact has been the Swedish Democrats, a Right-wing party that won 13 per cent of the vote at the general election in 2014.

A poll this week showed it is now backed by more than one in four Swedes.

It has been reported that six Afghan child refugees have committed suicide in Sweden in the past six months as the government attempts to care for 25,000 unaccompanied migrant children

Mattias Karlsson, leader of the party in the Swedish parliament, told me he was ‘very grateful to President Trump for focusing attention on this issue’, and expressed incredulity that the U.S. leader’s comments had proven so controversial.

‘Sweden is the most politically correct country in the world,’ he said.

‘For a long time, there have been no reports about the negative consequences of our open-door immigration policy because anyone who speaks out gets called a racist or a Nazi.

‘Riots like [that in Rinkeby] have become part of everyday life in Sweden.

‘We have huge problems with immigration and law and order. This is not only in Rinkeby. Now we have problems in our towns and cities that we did not dream could be possible ten years ago. People have had enough.’

So where did it all go so badly wrong for Sweden?

With a rapidly ageing population, the country began to welcome migrants from countries such as Turkey in the late Seventies, even arranging flights to bring in workers, who received the same generous welfare payments as locals.

But from 2011 onwards, the rate of immigration accelerated as those who arrived alone were allowed to send for their families once they were admitted. Many of these new arrivals are economic refugees.

Saeb Al-Saedy, a mechanical engineer originally from Baghdad, lives in Rinkeby and admits that there are ‘many really, really bad guys’ in the area.

Yet even so, he still blames the Swedish government for ‘oppressing’ immigrants. The unemployment rate among Swedes is 4 per cent, but among migrants it’s 22 per cent — partly because the job market is closely regulated.

‘When people don’t have any work, they take welfare and become criminals,’ Saeb told me. ‘Swedish people feel there are too many foreigners, and are scared of Islam. There are terrorists who are Muslims. But how many people were killed by Hitler?’

Such comments infuriate Swedes, who believe newcomers should be grateful to live in a country — funded by progressive personal taxation of up to 50 per cent for all earning more than £63,000 — with a generous welfare state offering free housing and healthcare for the unemployed.

But it is the rise in crime that causes most concern, particularly among women, some of whom told me they no longer go out at night in a country long regarded as being at the forefront of gender equality.

Anna, 27, an office worker, told me that because pepper spray is illegal in Sweden, she carries a can of ‘criminal identifier’ — an indelible spray paint that stays on the attacker. She hopes if she has to use it, it will disable an assailant long enough for her to flee.

‘I live in the area nearest to Rinkeby, where there is a shopping mall,’ she told me. ‘Gangs hang about in groups of 20 or more. They shout comments about me, and laughed when I used to go jogging.

‘I used to feel unsafe only after dark. Now, I feel scared even in daylight. I won’t even wear headphones in case I can’t hear someone creeping up to attack me.’

Such is the price that Sweden appears to be paying for its liberal and well-meaning policies, with a growing number of areas in its major cities where even the police fear to tread, let alone law-abiding citizens.

This may be an issue fraught with social and political complexities. But at its heart is the question increasingly convulsing nations across Europe: just how can they assimilate ever-growing number of migrants without creating dangerous social divisions that only serve to inflame extremism?