Work to defuse a large US aviation bomb from World War II unearthed in the western German city of Cologne ran into technical difficulties on Friday, following the evacuation of three nearby hospitals. According to city officials, specialists from the Explosive Ordnance Disposal Service were only able to defuse one of two detonators fitted to the unexploded 1000-kilogram bomb. It therefore had to be detonated in a controlled manner, the city announced. The evacuation radius and defined danger zone remained unchanged. Approximately 6,400 residents also had to leave their homes in what city offic…