Iran cancelled a UN inspector's accreditation after she triggered an alarm at a uranium enrichment plant.
The EU said on Thursday it was "deeply concerned" by an incident involving an inspector with the UN's nuclear watchdog last week in Iran which led to her having her accreditation cancelled.
In a statement delivered to a special meeting of the governing body of the International Atomic Energy Agency (IAEA), an EU representative said: "The EU is... deeply concerned by the incident concerning one IAEA inspector".
"We understand that the incident was resolved and call upon Iran to ensure that no such incidents occur in the future," the statement said.
Reiterating the EU's "full confidence in the inspectorate's professionalism and impartiality", the statement called "upon Iran to ensure that IAEA inspectors can perform their duties in line with its legally binding safeguards agreement".
Iran said on Thursday it had cancelled the inspector's accreditation after she triggered an alarm last week at the entrance to the Natanz uranium enrichment plant.
The alarm during a check at the entrance gate to the plant in central Iran had raised concerns that she could be carrying a "suspect product" on her, the Iranian Atomic Energy Organisation said in a statement posted online.
As a result, she was denied entry, it added, without specifying whether or not anything had been found in her possession.