Four people were killed and 15 injured when a stolen truck ploughed into a crowd of people outside a busy department store in central Stockholm Friday, police said, adding that one man had been arrested in connection with the attack.

It was the latest in a string of similar assaults with vehicles in Europe, including in London, Berlin and the southern French city of Nice.

Children were among the injured, Stockholm´s regional health care authorities said in a statement.

“Sweden has been attacked. Everything points to a terror attack,” said Prime Minister Stefan Lofven, who cut short a visit in southwestern Sweden to return to Stockholm after what, if confirmed, would be the country´s first deadly terror attack.

Police had earlier released a grainy picture of a suspect they did not have in custody.

Police spokesman Lars Bystrom refused to say whether the man who was later arrested was the man in the picture, and would not confirm media reports that he had confessed to the attack.

Police had earlier said two people had been taken in for questioning.

Pictures taken at the scene showed a large blue truck with a mangled undercarriage smashed into the Ahlens department store.

A spokeswoman for beer company Spendrups told AFP that the truck “had been stolen during a delivery to a restaurant.”