Swedish Prime Minister Stefan Lofven says "the country is in a state of shock" over a stolen beer truck attack that has killed four people and wounded 15 others in downtown Stockholm.
Lofven said on Friday "the aim of terrorism is to undermine democracy. But such a goal will never be achieved in Sweden".
Police have arrested one suspect in the truck attack but would not say if they are hunting for any others.
They discouraged people from going into central Stockholm on Friday night, and the national theatre, which is near the crash site, cancelled three plays.
Lofven said in a national televised address that his Social Democratic Party was still planning to hold its annual convention this weekend in Goteborg, Sweden's second-largest city.
