An explosion in the German town of Hemer, in the western North Rhine Westphalia state, caused the complete collapse of a block of flats, leaving three people seriously injured on Friday. Several others suffered minor wounds, while five people are still missing, a police spokeswoman said. The cause of the explosion is still unclear. According to reports, eight people were living in the block of flats. The area around the scene of the accident was widely cordoned off, while the surrounding houses were evacuated.