In 2003, the International Atomic Energy Agency (IAEA) confirmed the existence of previously undeclared nuclear facilities in Iran, in violation of its Safeguards Agreement under the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). Despite international calls, Iran refused to suspend proliferation-sensitive activities. In February 2006, the IAEA Board of Governors reported Iran’s nuclear program to the United Nations Security Council (UNSC). In response, the UNSC imposed a series of sanctions between December 2006 and June 2010 to curb Iran’s expanding nuclear capacity.