“Over the last few days, Iranian officials and International Atomic Energy Agency (IAEA) experts carried out their final discussions about the source of contamination,” an unnamed official told the agency.
“These negotiations ended Tuesday and the IAEA experts returned to Vienna on Wednesday,” the official added.
The talks come ahead of a rare visit to Tehran by IAEA chief Mohamed ElBaradei on Friday and Saturday aimed at resolving outstanding questions over the Iranian nuclear programme.
The talks are believed to have centred on uranium particle contamination found in the past by UN inspectors at the technical college of Tehran University.
The two sides have already held discussions about Iran’s past experiments with plutonium and its use of uranium-enriching P1 and P2 centrifuges. The uranium contamination represents the latest chapter to be opened in the talks.
The talks are in line with a timetable agreed by both sides in August for Tehran to provide more information over various areas of ambiguity in its nuclear programme.
Despite four years of investigation, the IAEA has never been able to confirm if the drive is peaceful.
A report published in December by the US intelligence community said Iran had halted a nuclear weapons drive in 2003. Iran insists its atomic programme has always been peaceful.
