Pakistan has denied reports that it will hand uranium-enriching components to United Nations inspectors investigating Iran's nuclear programme.
Critics ask why fuel-rich Iran needs nuclear energy
It earlier admitted the former head of its own programme, Abdul Qadeer Khan, gave Iran similar centrifuge parts.
Diplomats close to the inquiry told reporters that Pakistan would give the parts to a UN laboratory in Austria.
Pakistan's foreign ministry spokesman rejected the reports as baseless.
"Pakistan has not been asked to give centrifuges, nor will Pakistan do so," Jalil Abbas Jilani told reporters on Monday.
Mr Jilani said that Islamabad was co-operating with the UN inspectors, without providing any further details.
The reports out of Austria said earlier Pakistan would give used centrifuge parts to the UN inspectors so that they could be compared to centrifuges found in Iran with suspicious traces of uranium.
The UN's Vienna-based International Atomic Energy Agency (IAEA) has been investigating Iran's nuclear programme for the past two years.
While it has found no proof that Iran plans to build nuclear weapons, it has also been unable to confirm that the programme is entirely peaceful, as Iran insists.
The US accuses Iran, a state already rich in gas and oil, of pursuing atomic energy as a screen to develop nuclear weapons.
In 2003, the IAEA found traces of uranium in Iran that had been enriched to various levels, some of them close to what would be useable in weapons.
Fears then arose that Iran had been secretly seeking to purify uranium for use in weapons.
Iran blamed the traces on contaminated centrifuge components it had acquired second-hand from Pakistan.