FRANKFURT, Germany (AP) — A 500-kilo (1,100-pound) World War II bomb was defused near the Frankfurt headquarters of the European Central Bank hours after thousands of people were evacuated from the surrounding district Sunday. City officials called on about 16,500 people to leave their homes in the Ostend area east of downtown Frankfurt on Sunday morning before emergency workers tackled the American bomb, which was found during construction work last month. Authorities had already moved some people out of a nursing home on Saturday. More than 70 years after the end of the war, unexploded bombs are frequently found in Germany. Disposing of them sometimes entails large-scale precautionary evacuations such as the one on Sunday. The defusing operation was completed by mid-afternoon, according to the city's fire service, about two hours after police verified that no one was left in the area. Officials chose Sunday to defuse the bomb to allow preparation and to minimize disruption in Frankfurt, Germany's financial center.