There's been an explosion in Oslo close to the Prime Minister's office. Government buildings and a newspaper office have been damaged. The PM is unhurt, but there are injuries and at least one person dead. There's currently a rescue operation to get people out of damaged buildings.
http://www.bbc.co.uk/news/world-europe-14252515
As a small mercy, this occurred during a holiday, when far more people would have been inside the offices.