The man in custody suspected of carrying out the Stockholm truck attack has previously figured in intelligence material, Swedish security police said on Saturday (April 8).

National Police Chief Dan Eliasson told reporters that the suspect, a 39 year-old man from Uzbekistan, had previously featured in a security intelligence briefing and was know to be a "marginal character".

Eliasson also said they had found a "technical" device in the truck but stated officials did not yet know if it was a homemade bomb, as reported by public broadcaster SVT.

The attack was the latest to hit the Nordic region after shootings in the Danish capital Copenhagen killed three people in 2015 and the bombing and shooting in 2011 by far-right extremist Anders Behring Breivik that killed 77 people in Norway.