Police in Vienna have closed off the UN office in the Austrian capital, after a bomb threat came in by phone. The building, known as UNO City, also houses the United Nations Industrial Development Organization (UNIDO), the International Atomic Energy Agency (IAEA) and the United Nations Office on Drugs and Crime (UNODC). All vehicles passing in the area are being searched and this has led to huge traffic jams. Bomb squads have been sent to the area but have turned up nothing yet. The Vienna office is UN's third biggest in the world after the headquarters in New York and the Geneva Office.