Video footage has shown the immediate aftermath of the moment a lorry ploughed through a crowd in Sweden, killing at least three people.
Dozens of people can be seen running out of a major department store in downtown Stockholm after the truck hit. Five armed police officers can later be seen walking through the area.
Separate footage shows smoke rising from what appears to be the crash site as firefighters attempt to put out the fire, while emergency vehicles can be heard blaring in the background.
The incident occurred at Ahlens Mall in Drottninggatan, a shopping area of the city, which has now been cordoned off. Stockholm's Central Station for trains and the subway, which is a few hundred yards from the scene, was also evacuated.
Swedish broadcaster SVT said shots were fired at the scene, though it wasn't clear who fired them. One person has been arrested in connection with the incident.
A witness told Swedish daily paper Aftonbladet: “I went to the main street when a big truck came out of nowhere. I could not see if anyone was driving it but it got out of control.
"I saw at least two being run over. I ran as fast as I could from there.”
Another witness told the paper they saw hundreds of people “running for their lives” outside the shopping centre.
Swedish Prime Minister Stefan Lofven said everything indicates that a truck which has crashed into is “a terror attack.”
Broadcaster SVT said at least five people have been killed in the attack but police could not immediately confirm that, while Swedish radio reported that at least three people have died.
Swedish beermaker Spendrups said its truck had been carjacked earlier on Friday, according to reports.
The crash took place near the site of a December 2010 attack in which Taimour Abdulwahab, a Swedish citizen who lived in Britain, detonated a suicide bomb, killing himself and injuring two others.