Swedish Prime Minister Stefan Lofven says everything indicates that a truck which has crashed into a major department store in downtown Stockholm is "a terror attack.''
He also says one person has been arrested.
Lofven says at least two people have been killed in the attack Friday afternoon on the Ahlens store.
Broadcaster SVT says at least five people have been killed in the attack but police could not immediately confirm that. Swedish radio says at least three people have died.
The Aftonbladet daily says Swedish beermaker Spendrups said its truck had been carjacked earlier Friday.
The most recent attack in Stockholm was on Dec. 11, 2010, when an Iraqi-born Swede, Taimour Abdulwahab al-Abdaly, detonated two devices, including one that killed him, in central Stockholm.