A blaze ripped through an apartment building in Norway's capital early Saturday, killing six people and injuring 12, police said. Joern-Kristian Joergensen, an Oslo police spokesman, said one person was taken to the Ullevaal University hospital with serious injuries. Some 30 people were evacuated and everyone in the five-floor building had now been accounted for. Norwegian news agency NTB reported that several people were rescued with ladders after they had climbed out onto the roof. Joergensen said the cause of the fire remained unclear but police had launched an investigation to establish how and where it started. The victims have not yet been identified. Firefighters took more than two hours to bring the fire under control.