The latest round of U.S.-Iran negotiations ended without a deal. U.S. negotiators demanded that Iran dismantle its nuclear facilities at Fordow, Isfahan, and Natanz and turn over its remaining enriched uranium stockpile to the United States, and they insisted that the terms of any deal have no expiration. Iran rejected transferring its enriched uranium abroad and objected to ending enrichment, destroying nuclear sites, or permanent limits on its nuclear program. Iran proposed reducing its enrichment level to 1.5%, pausing enrichment for a period of years, or enriching uranium through an Arab-Iranian consortium based in Iran. The United States may consider allowing Iran to enrich a limited amount of uranium for its research reactor in Tehran, according to U.S. officials. The talks took place in Geneva and were mediated by Oman's foreign ministry, which said technical experts would continue to negotiate in Vienna the following week. Meanwhile, an additional destroyer joined the U.S. fleet in waters near Iran, and a U.S. aircraft carrier approached the Eastern Mediterranean. U.S. Secretary of State Marco Rubio said Iran's refusal to discuss its ballistic missile program was a major problem for the United States.