Iran's nuclear body has denied claims by a senior MP that it has begun installing 3,000 nuclear centrifuges to boost its uranium enrichment.
Iran has demanded the removal of a key UN official
Hossein Simorgh, of Iran's Atomic Energy Organisation, said there were no new centrifuges at its Natanz plant.
The earlier claim was made by Alaeddin Boroujerdi, head of the foreign affairs and national security committee.
Some Western nations fear Iran is trying to build nuclear arms but Tehran insists its programme is peaceful.
Mr Simorgh, the head of public affairs at the Atomic Energy Organisation, told Iran's Irna news agency: "No new centrifuge machine has been installed at the Natanz facility."
Earlier, Mr Boroujerdi said that "God willing" the work would be "finished in due time".
UN SANCTIONS ON IRAN
Ban on import and export of nuclear-related material
Assets frozen of 10 companies and 12 individuals
Threat of further non-military sanctions
Centrifuges spin uranium hexafluoride gas to produce enriched uranium by raising the concentration of fissionable isotopes, at low levels of concentration for fuel and much higher levels for nuclear weapons.
The new centrifuges would massively increase Iran's potential to produce nuclear material.
On Friday Iran demanded the removal of the UN official in charge of inspecting the country's nuclear programme.
The official, Chris Charlier, had already been banned from entering Iran.
Earlier in the week, Iran banned 38 inspectors from four different countries.
The UN Security Council passed a resolution on 23 December banning the supply of nuclear-related technology and materials to Iran and imposing an asset freeze on key individuals and companies.