From the Summary: "International Atomic Energy Agency (IAEA) inspections since 2003 have revealed two decades' worth of undeclared nuclear activities in Iran, including uranium enrichment and plutonium separation efforts. Iran agreed in 2003 to suspend sensitive activities in negotiations with Germany, France, and the UK (EU-3), which broke down in August 2005. On September 24, 2005, the IAEA Board of Governors found Iran to be in noncompliance with its Nuclear Nonproliferation Treaty (NPT) safeguards agreement and reported Iran's case to the U.N. Security Council in February 2006. The Security Council called upon Iran to resuspend enrichment and reprocessing, reconsider construction of its heavy water reactor, ratify and implement the Additional Protocol, and implement transparency measures. Iran continued enrichment activities and failed to meet the Security Council's request, even after the permanent members plus Germany (P-5 +1) offered Iran a new proposal on June 6. The Security Council passed UNSCR [United Nations Security Council Resolution] 1696 on July 31, 2006, giving Iran a deadline of August 31 to comply. Iran failed to suspend enrichment, resulting in passage of UNSCR 1737 sanctions on December 23, 2006. This report will be updated as needed."
CRS Report for Congress, RS21592