JUST IN: Big explosion in Stockholm (Sweden)… Witnesses described the blast as “powerful”.

http://www.independent.co.uk/news/world/europe/stockholm-explosion-live-large-blast-hits-centre-of-swedish-capital-a6723996.html

“A powerful explosion has been heard and a window is broken. Police are investigating what caused the explosion and whether it is related to the broken windowpane,” Stockholm police said in a statement.