United Nations' atomic watchdog chief Yukiya Amano expressed "great regret" Monday at Iran 's decision to bar key inspectors from the country, saying it hampered the agency's ability to carry out its investigation.

"I learned with great regret about
Iran 's decision to object to the designation of two inspectors who recently conducted inspections in Iran ," Amano told the 35-member board of the International Atomic Energy Agency.

"
Iran 's repeated objection to the designation of inspectors with experience in Iran 's nuclear fuel cycle and facilities hampers the inspection process," he said, according to a copy of his speech.

Amano made his comments in the opening address to the closed-door meeting of the board of governors being held this week.

In a restricted report circulated to board members last week, Amano had already complained about
Iran 's so-called "de-designation" of inspectors, particularly in the recent cases of two experienced inspectors who had their permits revoked after Iran alleged they had made "false" reports.

But Amano stood by his staff Monday.

"I express my full confidence in the professionalism and impartiality of the inspectors concerned," he said. "Both are very knowledgeable about the nuclear fuel cycle and have long experience in
Iran ."

It wasn't the first time that
Iran has objected to the nomination of key inspectors, Amano pointed out.

"I call upon
Iran once again to reconsider its decision of Jan. 16, 2007 to request the agency to withdraw the designation of 38 inspectors," he said.

Tehran 's envoy to the IAEA, Ali Asghar Soltanieh, said he "categorically" rejected the suggestion that the barring of two inspectors could hamper the agency's work.

"I categorically reject this statement," Soltanieh told reporters.

"They're trying to make an issue [out of this]," he said, insisting it was
Iran 's right, under the terms of its safeguards agreement with the agency, to vet inspectors. Furthermore, member states weren't obliged to provide a reason for such a decision.

It was "ridiculous" for the agency to complain about the decision to bar just two inspectors when there was a pool of "over 150 inspectors" to draw from, Soltanieh said.

He complained that neither Amano's written report, nor his comments to the IAEA board on Monday, were "balanced" since they didn't give the full picture.