Some form of explosive loading has required evacuation of an exterior cellar staircase in Hägernäs. No person has been found injured so far.
The demand has caused limited damage to the stairs. A window has been smashed.
The police have launched an investigation into malicious destruction and serious crime against the Act on Flammable and Explosive Substances - LBE.
A comprehensive police operation is underway in northern Stockholm, where a suspected perpetrator is being sought.