U.S. Secretary of State Mike Pompeo has called Iran's treatment of a UN nuclear inspector in late October "an outrageous and unwarranted act of intimidation."
Pompeo said on November 8 that Tehran "detained" the inspector from the International Atomic Energy Agency (IAEA), which had reported she was briefly prevented from leaving Iran.
"The United States fully supports the IAEA's monitoring and verification activities in Iran, and we are alarmed at Iran's lack of adequate cooperation," Pompeo said in a statement.
"IAEA inspectors must be allowed to conduct their critical work unimpeded. We call on Iran to immediately resolve all open issues with the IAEA and to afford agency inspectors the privileges and immunities to which they are entitled," he added.
Behrouz Kamalvandi, a spokesman for Iran's Atomic Energy Organization (AEO), defended the move by saying the Iranian government -- "legally speaking" -- had done nothing wrong during the October 28 incident.
Iran says it canceled the inspector's accreditation after an alarm at the entrance to the Natanz uranium-enrichment plant raised concerns she could be carrying a "suspect product" on her.
Tehran says she was denied entry to the facility because she had tested positive for suspected traces of explosive nitrates.
The IAEA dismissed the Iranian claim.
"The reason that this lady was denied entrance was that she was suspected of carrying some material," Kamlavandi said, adding that Iran was exercising its "rights" under its agreement with the IAEA when it blocked her entrance and revoked her accreditation.
"We welcome the inspections," he said, adding that inspections cannot be used for "sabotage and leaking information."
Kazem Gharib Abadi, Iran's ambassador to the IAEA, told reporters in Vienna that after setting off the alarms, the inspector "sneaked out" to a bathroom while awaiting a more thorough inspection with a device that can detect explosive material.
Upon her return, he said, the alarms did not go off again. He claimed authorities later found contamination in the bathroom and on her empty handbag.
Iran said IAEA officials were present for all the searches.
Last year, the United States pulled out of a 2015 nuclear deal Tehran signed with six world powers, in which Iran agreed to curb its nuclear program in exchange for sanctions relief..
Since the U.S. withdrawal, Iran has progressively scaled back commitments under the accord.
Kamlavandi announced another step away from those commitments by Iran on November 9, saying Iran had started to enrich uranium at the Fordow nuclear site on November 7.
Under the terms of the 2015 nuclear accord, the low-level enrichment of uranium at the Fordow facility in order to produce nuclear fuel was not supposed to take place until 2030
Britain, China, France, Germany, and Russia have remained in the deal and have attempted to mitigate the damages caused to Iran’s economy by renewed U.S. sanctions.