Uzbek Suspect in Stockholm Attack Had Ignored Deportation Order, Police Say

People leave flowers on the steps at Sergels Torg following the terror attack in central Stockholm, Sweden, April 9. TT News Agency/Reuters

An Uzbek man suspected of ramming a truck into a crowd in Stockholm, killing four people, had expressed sympathy for the Islamic State militant group (ISIS) and was wanted for failing to comply with a deportation order, Swedish police said on Sunday.

Another 15 people were injured on Friday when a hijacked beer delivery truck barreled down a busy shopping street before crashing into a department store and catching fire. The Uzbek man was arrested several hours later.

"We know that the suspect had expressed sympathy for extremist organizations, among them IS," Jonas Hysing, chief of national police operations, told a news conference, using an acronym for the ultra-hardline militant group.

In Europe, vehicles have also been used as deadly weapons in attacks in Nice, Berlin and London over the past year and were claimed by ISIS. There has been as yet no claim of responsibility for the Stockholm assault.

The Stockholm suspect, aged 39 and from the Central Asian republic of Uzbekistan, applied for permanent residence in Sweden in 2014. But his bid was rejected and he was wanted for disregarding an order for his deportation, Hysing said.

Police had been looking for him since the Nordic country's Migration Agency in December gave him four weeks to leave the country. He had not been known as a militant threat by the security services before Friday's attack.

Two of the dead were Swedes, one was a British citizen and the other from Belgium, Hysing said.

Sweden's prosecution authority said a second person had been arrested in connection with the attack on suspicion of having committed a terrorist offense through murder.

But police said they were more convinced than ever that the Uzbek man was the driver of the commandeered truck.

They said another five people were being held for questioning after raids during the weekend, and that they had conducted about 500 interviews as part of the inquiry.

Of the injured, 10 remained in hospital, two of them in intensive care.

Stockholm was returning to normality on Sunday with police barricades taken down along the Drottninggatan street where the attack took place.

Hundreds of flower bouquets covered steps leading down to the square next to where the truck ploughed into the Ahlens department store, with more piled up under boarded-up windows.

A memorial service was being held in Sergels torg, the central square next to Drottninggatan, at 2 p.m. (1200 GMT).

Prime Minister Stefan Lofven, addressing a Social Democratic party conference in the western city of Gothenburg, said Sweden would never be broken by acts of terror.

"We will hunt down these murderers with the full power of Sweden's democracy. There will be no compromises," he said.