Experts disposed of four unexploded World War II bombs in a western German city in an operation Sunday that prompted authorities to evacuate some 15,000 residents. The bombs were found near empty houses in Osnabrueck, some of which once accommodated families of British soldiers stationed in Germany, city spokesman Sven Juergensen said. The devices, believed to have been dropped by British planes during wartime raids, were located with the help of aerial photographs. Two of them were defused, and the other two destroyed in controlled explosions. Authorities decided to evacuate 15,000 people from the surrounding district as a precaution ahead of Sunday's operation, also relocating patients from three nearby hospitals.