The Prime Minister of Sweden has vowed his country will 'never go back' to recent levels of mass immigration after it emerged the terrorist who killed four people in a truck attack was a failed asylum seeker.

Stefan Löfven pledged to change his country's liberal attitude, insisting the massive influx allowed during the 2015 migrant crisis would never happen again.

Rakhmat Akilov, from Uzbekistan, hijacked the lorry and deliberately drove into pedestrians on central Stockholm's main shopping street on Friday afternoon.

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Sweden's prime minister, Stefan Löfven (pictured at a memorial in central Stockholm), has furiously demanded that illegal immigrants be sent home

Swedish Prime Minister Stefan Lofven and the royal family obse... Swedish Prime Minister Stefan Lofven and the royal family observe a minute's silence to honor the victims of the Stockholm truck attack that killed four Posted by Daily Mail on Monday, 10 April 2017

It was a copycat of the attack carried out in London last month, when Khalid Masood killed four pedestrians and injured dozens more with a Hyundai 4x4. Swedish police said there were clear similarities.

Akilov is thought to have carried out reconnaissance along his route days earlier.

Four were killed and 15 injured when he drove a 30-ton truck down a pedestrianised area and smashed into a department store. Chris Bevington, a 41-year-old father-of-two from Britain, was killed close to his office.

But it emerged yesterday Swedish authorities had given Akilov four weeks to leave Sweden after his final asylum appeal failed in December.

He was being sought by police and immigration officials for deportation – but evaded them simply by giving a false address.

'Sweden will never go back to the [mass migration] we had in autumn 2015, never,' Mr Löfven said yesterday.

'Everyone who has been denied a permit should return home.

'This makes me feel enormously frustrated. If you have been denied a visa you are supposed to leave the country.'

Alleged terrorist: The 39-year-old man from Uzbekistan suspected of driving the truck which injured 15 and killed four has been named as Rakhmat Akilov

He added: 'Terrorists want us to be afraid, want us to change our behaviour, want us to not live our lives normally, but that is what we're going to do.

'Terrorists can never defeat Sweden, never.'

There are more than 3,000 migrants living unlawfully in Stockholm alone, police said.

Akilov, 39, had expressed support for Islamic State and world-wide extremist group Hizb ut-Tahrir, whose UK members included jailed hate preacher Anjem Choudary.

Akilov reportedly told police that he carried out the attack on the orders of Islamic State.

He allegedly said: 'The bombings in Syria must stop,' a Swedish newspaper reported.

Akilov has allegedly confessed to the attack and told investigators he was 'pleased with what he had done' and had 'accomplished what he set out to do', it was claimed.

Police sources said a bomb, found in the truck but which failed to detonate, contained gas canisters, chemicals and nails.

Hero: Orthopedic surgeon Joakim Nordahl, 54, was in his surgery when he heard the attack, picked his gloves and emergency bag and went straight out with another seven people from the reception

As Sweden contemplates the first Islamic State-inspired attack to claim lives on their soil, it also emerged that:

The Swedish intelligence agency SAPO admitted that Akilov had previously been on their radar;

Thousands attended a vigil where they laid a sea of flowers, candles and toys;

A security guard saved lives by blocking the lorry with his van during the attack;

Two Swedes, including an 11-year-old girl walking home from school, and a 31-year-old Belgian tourist were also killed.

Prosecutors were last night questioning a potential accomplice. A further four men, whose details have yet to be revealed, were also being held in police custody.

Nine of the 15 victims injured are still being treated in hospital, four of whom remain in a serious condition. Two of those are in intensive care.

Akilov, a father-of-four from Uzbekistan, lived in a shabby apartment in Stockholm.

The construction worker applied to the Swedish migration board for a residency permit in November 2014, but was turned down in June 2015.

After his appeal was subsequently refused in 2016, he avoided deportation by giving police a false address.

During one interview, he allegedly told an employer that he was an expert in explosives.

Candles and flowers placed at the Sergels Torg to commemorate the victims of last Friday's terror attack in Stockholm, Sweden, on Sunday

But in recent weeks he shunned work, allegedly telling friends: 'I only smoke and sleep.'

The suspect was friends with key figures in the extremist Islamist group Hizb ut-Tahrir, including its leader in Sweden, and shared ISIS propaganda.

Akilov revelled in his support for the group and voiced his approval at its fanatical beliefs.

He also publicly supported Bilal Philips, a well-known Canadian Muslim preacher who has appeared to condone suicide bombing and has claimed there can be no rape in marriage.

But Akilov also dreamed of living a life of luxury – on one occasion sharing a picture of a plump sultan lying on a mattress eating grapes, with eight women wearing veils waiting on him.

He wrote: 'I would like to live that way. Not bad, brother!'

Akilov allegedly told a friend about his plans to carry out the atrocity days earlier.

'By tomorrow night I'd like to find a big car and to drive into the crowd,' he allegedly wrote.

He was captured after tip-offs from the public about a man who was confused and acting strangely in the suburb of Marsta, close to the international airport.

When his friend asked him how he was, Akilov is said to have replied: 'Bad, I have driven over several people, the car drove the wrong way. I am in the airport now, dead end.'