Iran's stock of uranium enriched to up to 60 percent, close to weapons-grade, and has grown to well above the amount that by one definition is enough, if enriched further, for a nuclear bomb, International Atomic Energy Agency said in a report.
The quarterly report by the UN atomic watchdog was released on Wednesday.
Iran's uranium enriched to up to 60 percent and in the form of uranium hexafluoride, the gas that centrifuges enrich, is estimated to have grown by 12.5 kg to 55.6 kg since the last quarterly International Atomic Energy Agency (IAEA) report issued on May 30, the IAEA report to member states seen by Reuters said.
Although the US, Israel and other Middle East states have expressed concerns about Iranian nuclear enrichment for military purposes, Tehran denies that intends to build an atomic bomb.
Iran is already enriching uranium to a fissile purity of up to 60 per cent, far above a cap of 3.67 per cent set under the country's now tattered 2015 nuclear deal with world powers.
Uranium enriched to 90 per cent is required to make a nuclear bomb.