On February 7, 2010, Iranian President Mahmoud Ahmadinejad announced that Iran would begin producing up to twenty percent enriched uranium in order to fuel its Tehran Research Reactor (TRR). The next day, Iran told the International Atomic Energy Agency (IAEA) that this work was planned for the Pilot Fuel Enrichment Plant (PFEP) at Natanz and that a portion of the country's stockpile of low-enriched uranium hexafluoride would be moved to the plant for further enrichment. On February 9, without the presence of IAEA inspectors, Iran began to produce 19.75 percent enriched uranium, using one cascade of 164 first-generation centrifuges. Enrichment levels of up to 19.8 percent were achieved by February 11th and by February 14th Iran had moved most of its low-enriched uranium stockpile - nearly two tons - to the PFEP. The world has condemned Iran's action, which brings Iran's nuclear stockpile much closer to weapon-grade and violates U.N. Security Council resolutions demanding that Iran cease all enrichment.

Read reactions and analysis from around the world:

The Wisconsin Project shows how Iran's decision to further enrich its uranium stockpile brings Iran closer to producing bomb fuel, 2-25-10.

U.S. officials condemn Iran's decision to enrich uranium up to twenty percent in violation of U.N. Security Council resolutions, and call on Iran to constructively engage in negotiations of a fuel swap or face sanctions: President Barak Obama, Secretary of State Hillary Clinton, Chairman of the Joint Chiefs of Staff Mike Mullen, and State Department spokesperson, 2-10.

Iranian President Mahmoud Ahmadinejad declares that Iran delivered the first batch of twenty percent enriched fuel to the TRR on February 11, 2010. President Ahmadinejad also states that Iran is ready for a fuel swap, 2-16-10.

E.U. High Representative for Foreign Affairs and Security Policy Catherine Ashton says that Iran's enrichment activity is unlikely to successfully refuel the TRR in time to produce medical isotopes, 2-9-10. (PDF)

Canadian Prime Minister Stephen Harper appeals to Iran to immediately halt its enrichment activity and cooperate with the IAEA, 2-8-10.

Australian Minister of Foreign Affairs Stephen Smith is concerned about Iran's uranium enrichment and is ready to support new sanctions, 2-8-10.

Japanese Minister of Foreign Affairs Katsuya Okada: Iran's decision to produce 20 percent enriched uranium damages the foundations of the IAEA proposal for fuel supply to the TRR, 2-8-10.

Russian Foreign Minister Spokesman Andrei Nesterenko expresses disappointment that Iran started twenty percent enrichment and encourages Iran to participate in diplomacy to implement a fuel swap, 2-9-10.

Chinese Ministry of Foreign Affairs Spokesman Ma Zhaoxu urges all parties in the P5+1 to reach an agreement about the IAEA fuel swap proposal through diplomacy, 2-9-10.

The IAEA reports on Iran's enrichment activities at the PFEP involving a small quantity of LEU, 2-18-10. (PDF) An earlier IAEA report describes steps taken by Iran to prepare for further enrichment, 2-10-10. (PDF)

Arms Control Wonk explains why producing 20 percent material would bring Iran much closer to bomb fuel, 2-9-10; provides the text of a letter sent to IAEA Director-General Amano from the U.S., Russian, and French ambassadors to the Agency condemning Iran's enrichment announcement as an "escalation," 2-12-10.

The Institute for Science and International Security (ISIS) analyzes Iran's capacity to produce twenty percent enriched uranium, how much such material Iran would need to fuel the TRR and the potential for "breakout" that would result, 2-8-10. ISIS published additional analysis on the TRR's capabilities on February 9, 2010 (PDF), and issued a report addressing enrichment developments in Iran on February 18, 2010 (PDF).