Iran's total production of low-enriched uranium has risen by around 15 percent since May to reach 2.8 tons, a UN nuclear watchdog report said, showing Tehran is pushing ahead with disputed work despite tougher sanctions.
The confidential report, obtained by Reuters on Monday, said the International Atomic Energy Agency (IAEA) remained concerned about possible activity in the Islamic Republic to develop a nuclear payload for a missile.
The IAEA also voiced concern about what it called Iran's "repeated objection" to the agency's choice of inspectors working in the country, after Tehran barred two UN nuclear inspectors from entering in June.
"The agency rejects the basis upon which Iran has sought to justify its objection," the report said, also referring to earlier cases where Iran raised such objections.
"It is also concerned that the repeated objection to the designation of experienced inspectors hampers the inspection process and detracts from the agency's ability to implement safeguards in Iran," it added.
Western powers are likely to see the report's findings as backing up their suspicions that Tehran is seeking to build nuclear bombs and underlining the need for the country to enter serious negotiations to curb its nuclear program.