The stock of uranium enriched to near weapons grade has grown sharply in Iran, according to two confidential reports by the UN nuclear watchdog. The stock of uranium enriched to up to 60% fissile purity, close to bomb-grade, has been a concern for Western powers. The International Atomic Energy Agency (IAEA) has expressed serious concern over Iran's increased production and accumulation of high enriched uranium. The IAEA reports also highlight the lack of progress on outstanding issues, including the unexplained presence of uranium traces at undeclared sites.