The Office of Foreign Assets Control of the U.S. Department of Treasury implements and enforces economic sanctions against foreign countries and organizations that threaten the national security, foreign policy or economy of the United States. These groups include oppressive governments, terrorists and narcotics traffickers.
The goal of OFAC is to enforce sanctions by stopping prohibited trade or financial transactions. OFAC prevents U.S. citizens from engaging in any of these activities unless the transactions are authorized by OFAC or are specifically exempted from sanction by law. Each set of sanctions, called a program, is based on different foreign policy and national security goals, so programs differ for each country or organization, as do the reasons for the sanctions. For example, since the Communist party took control of Cuba in the 1960s, the United States has used economic sanctions to attempt to isolate Cuba and encourage democracy. Most commercial activity with Cuba is restricted and requires an OFAC license. The sanction program in the Balkans blocks the property of anyone who threatens the international efforts to stabilize the western Balkans.
As of 2014, in addition to Cuba and the Balkans, countries currently sanctioned include Belarus, Burma, Ivory Coast, Democratic Republic of Congo, Iran, Iraq, Liberia, North Korea, Sudan, Syria and Zimbabwe.