Iran said Thursday it had cancelled the accreditation of a UN nuclear inspector after she triggered an alarm last week at entrance to the Natanz uranium enrichment plant.
The check at the entrance gate to the plant in central Iran had "triggered an alarm" raising concern that she could be carrying a "suspect product" on her, the Iranian Atomic Energy Organization said in a statement posted online.
Iran resumed uranium enrichment at its underground Fordow plant south of Tehran on Thursday in a new step back from its commitments under a landmark 2015 nuclear deal.
Engineers began feeding uranium hexafluoride gas into the plant's mothballed enrichment centrifuges in "the first minutes of Thursday", a statement said.
The suspension of uranium enrichment at the long secret plant was one of the restrictions Iran had agreed to on its nuclear program in return for the lifting of UN sanctions.
Iran's announcement on Wednesday that it would resume enrichment at the Fordow plant from midnight (2030 GMT) had drawn a chorus of concern from the remaining parties to the troubled agreement.
Britain, China, France, Germany and Russia have been trying to salvage the hard-won deal since Washington abandoned it in May last year and reimposed crippling unilateral sanctions.
They say Iran's phased suspension of its obligations under the deal since May makes that more difficult.
The resumption of enrichment at Fordow is Iran's fourth move away from the deal.