Prodded by the United States with threats of fines and lost business, four of the biggest European banks have started curbing their activities in Iran, even in the absence of a Security Council resolution imposing economic sanctions on Iran for its suspected nuclear weapons program. Top Treasury and State Department officials have intensified their efforts to limit Iran-related activities of major banks in Europe, the United States and the Middle East in the past six months, invoking antiterrorism and banking laws. Full Story