VIENNA (Reuters) - The United Nations nuclear watchdog and Western powers on Thursday strongly criticized Iran for preventing one of the agency’s inspectors from leaving the country last week.

U.S. Ambassador to the International Atomic Energy Agency (IAEA) Jackie Wolcott waits for the start of a board of governors meeting at the IAEA headquarters in Vienna, Austria, November 7, 2019. REUTERS/Lisi Niesner

The U.S. envoy to the International Atomic Energy Agency said detaining the inspector was an “outrageous provocation” by Iran and the agency itself said it was unacceptable.

Reuters first reported on Wednesday that Iran had held the IAEA inspector and seized her travel documents in what appears to be the first incident of its kind since Iran’s nuclear deal with major powers was struck in 2015.

Iran confirmed on Wednesday that it prevented the inspector from gaining access to its main uranium-enrichment facility at Natanz. The IAEA said on Thursday that one of its inspectors was “temporarily prevented from leaving Iran” last week.

"The detention of an IAEA inspector in Iran is an outrageous provocation," the U.S. ambassador to the IAEA, Jackie Wolcott, said in a statement here to an emergency meeting of the IAEA's 35-nation Board of Governors.

“All Board members need to make clear now and going forward that such actions are completely unacceptable, will not be tolerated, and must have consequences.”

Iran’s envoy to the IAEA told reporters the inspector was stopped because she tested positive for traces of explosives but then no longer did after going to the toilet while waiting for a further search, which prompted further investigation.

Iran also circulated a memo to member states describing in detail the incident that it said began around 11 a.m. on Oct. 28, including that the inspector “sneaked out to go to the WC” and that “alarming signals” were found on a toilet bowl and parts of exit piping, which were dismantled for checks.

The inspector left Iran on Oct. 30, the memo obtained by Reuters said.

“The agency does not agree with Iran’s characterization of the situation involving the inspector,” an IAEA spokesman said in a statement. “Preventing an inspector from leaving a country ... is not acceptable and should not occur.”

“SUSPICIOUS MATERIALS”

The European Union said it was “deeply concerned” by what happened.

“We understand that the incident was resolved and call upon Iran to ensure that no such incidents occur in the future,” an EU statement said.

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Iran’s ambassador to the IAEA Kazem Gharibabadi said Tehran had asked that she be removed from the list of designated inspectors, adding: “There is no doubt that there were suspicious materials involved in this incident.”

Acting IAEA chief Cornel Feruta, who will be succeeded by Argentina’s Rafael Grossi next month, called Thursday’s board meeting to discuss the incident and Iran’s failure to give a convincing explanation for uranium traces found at a site in Tehran.

Feruta told Iran in September that “time is of the essence” in addressing the IAEA’s questions on how it found the traces on samples taken in February at the undeclared site, which Iran has said was a carpet-cleaning facility.

The EU and United States called on Iran to cooperate with the IAEA in explaining the traces of uranium that was processed but not enriched. A U.S. official said there were also signs of “activities consistent with sanitization” by Iran there.

“Time was of the essence in September; now that time is up,” Wolcott, the U.S. envoy, said in her statement.