The U.N.'s International Atomic Energy Agency offered a rare statement to journalists on Thursday after Iran's representative made the claim in Vienna. The IAEA says that the "agency does not go into details in public about such matters, but based on the information available to us, the agency does not agree with Iran's characterization of the situation involving the inspector, who was carrying out official safeguards duties in Iran."
The IAEA added that it will "consult with Iran with a view to clarifying the situation."
Iran is alleging that a U.N. inspector it blocked from a nuclear site last week had tested positive for explosive nitrates.
Iran's representative to the International Atomic Energy Agency, Kazem Gharibabadi, made the allegation on Thursday at a suddenly called meeting in Vienna.
He did not elaborate on why he thought the woman had the residue on her, though he said she went to the bathroom while waiting for a secondary screening and apparently removed the material. This happened at Iran's Natanz nuclear facility.
There was no immediate comment from the IAEA.
This incident comes amid heightened tensions between Iran and the U.S. over its nuclear program.
Iran has injected uranium gas into centrifuges deep inside its underground Fordo nuclear complex.
Thursday's move is Tehran's most-significant step away from its 2015 nuclear deal with world powers.
It also puts additional pressure on Europe to offer Iran a way to sell its crude oil abroad despite the U.S. sanctions imposed on the country since President Donald Trump unilaterally withdrew America from the nuclear deal over a year ago.
Tehran meanwhile also acknowledged blocking an official from the International Atomic Energy Agency from visiting its nuclear site at Natanz last week, the first known case of a United Nations inspector being blocked amid heightened tensions over its atomic program. Iran's representative to the IAEA said Tehran had asked the agency never to send the inspector again, without elaborating on what happened.