Iran stepped up enrichment on June 6, the same day European Union foreign policy chief Javier Solana visited Tehran to present a package of benefits aimed at halting Iran’s uranium enrichment program.
The report said Iran started feeding the raw material of uranium hexafluoride gas, or UF6, into a connected series of 164 centrifuges – known as a cascade - to produce enriched uranium.
Iran is also building new production lines of the centrifuges that carry out the sensitive nuclear work. The International Atomic Energy Agency’s confidential report will be discussed by the IAEA's 35-nation board of governors next week in Vienna.
The damaging report appears to dash hopes Iran is preparing an immediate suspend in its nuclear fuel activities in order to start talks with six major powers on guaranteeing its program is peaceful.
"This just shows that there's a long way to go before there's a deal," nuclear analyst David Albright told AFP from his ISIS think tank in
Washington.
The report also said IAEA inspectors had found new traces of highly enriched uranium on equipment on Iran.
But it was unclear whether the enriched uranium traces were contaminants from equipment Tehran had purchased abroad or from enrichment that had been carried out by Iran.
According to the report Iran had also failed to clear up IAEA questions over high-tech centrifuges it may have acquired.
It also left unanswered questions over secret military projects that could be related to making nuclear weapons and failed to comply with a request to halt work on a heavy-water reactor that would make plutonium, another potential atomic weapons material.
Report not ‘crucial’
A European diplomat in Vienna described the report as negative on all accounts for Iran.
But the diplomat said this was not "crucial" since what mattered was getting Iran and the US-led "Iran six" of world powers to find a way of holding talks.
Tehran says it is seeking solely to develop a civilian nuclear power program but Washington and the European Union fear this is a cover for building nuclear weapons.
Iran built the cascade as a pilot plant for what it hopes will eventually be an industrial plant of more than 50,000 centrifuges, used to refine out the uranium 235 isotope.
At no time had Iran actually halted feeding uranium gas into centrifuges since making a first batch on April 11, a UN official said.
During a pause in feeding the 164-centrifuge cascade, but leaving it running empty for technical reasons, it had fed the gas into two single centrifuge machines.
London-based analyst Mark Fitzpatrick said: "This will strengthen Washington's resolve that full and complete suspension of Iran's nuclear fuel program has to be a condition for negotiations to begin, including no centrifuges spinning at all."
A UN official said the Iranians had fed "10s of kilos into the system so far" and have produced only small amounts, "grams and hundreds of grams," of enriched uranium.
Iran also has produced 118 tonnes of uranium hexafluoride gas at its Isfahan plant since August. The "new conversion campaign" that began June 6 involved more than 30 tonnes of uranium ore to be converted into uranium gas, a senior UN official said.
Experts say that these quantities would yield enough material for over 20 nuclear bombs, experts say.