It listed all the targets of the bombing, which included: the royal palace, the war ministry, military headquarters, the central post office, the telegraph office, passenger and goods railway stations, power stations and barracks. It also mentioned that seven aerial mines were dropped, and that areas in the centre and northwest of the city had been destroyed, comprising 20 to 25 percent of its total area. Some aspects of the bombing remain unexplained, particularly the use of the aerial mines.[184] In contrast, Pavlowitch states that almost 50 percent of housing in Belgrade was destroyed.[185] After the invasion, the Germans forced between 3,500 and 4,000 Jews to collect rubble that was caused by the bombing.[186]