International Atomic Energy Agency Director General Yukiya Amano speaks to reporters Aug. 5 after briefing the Senate Foreign Relations Committee on the Iran nuclear accord. (Michael Mathes/AFP/Getty Images)

The international watchdog agency charged with verifying Iran’s compliance with the recent nuclear deal said Thursday that critics of the deal “misrepresent” its plans for doing so.

In an unusual rebuttal from his headquarters in Vienna, International Atomic Energy Agency ­Director General Yukiya Amano said he was “disturbed” by suggestions “that the IAEA has given responsibility for nuclear inspections to Iran.”

Amano’s statement came after deal opponents seized on a news service account of IAEA plans to assess the “possible military dimensions,” or PMDs, of Iranian nuclear activity before 2003 to expand their criticism of the broader agreement restricting Iran’s future nuclear program. U.S. intelligence has said that 2003 was when Tehran stopped trying to develop an atomic weapon.

The Associated Press reported from Vienna that it had obtained a copy of an IAEA-Iran draft agreement on PMDs indicating that Iran would be allowed to collect its own samples at Parchin military complex for IAEA inspection. According to U.S. intelligence, the suspect activities were based primarily at Parchin.

Under IAEA rules, the PMD document is confidential between the signing parties. While it technically is not part of the broader accord negotiated between Iran and world powers, that agreement cannot go into effect until the IAEA certifies it is satisfied with the PMD inspections.

The PMD issue, and indirect IAEA access to Parchin, has been raised repeatedly in congressional hearings since the larger agreement was completed July 14. Congress has until Sept. 17 to review the deal. A vote of disapproval, requiring a simple majority, is seen as assured, because virtually all Republicans are expected to oppose it.

The administration has said it believes it could sustain a veto of such legislation, with enough Democratic votes to prevent an override requiring two-thirds of both chambers.

Proponents and opponents of the deal have been lobbying heavily, with visits to lawmakers and their districts, full-page newspaper ads and television commercials. Israel’s government is resolutely opposed to the agreement, and American Jewish groups have been heavily involved on both sides of the issue.

Supporters of the deal charge that critics have conflated the Parchin issue with what they insist is a rigorous international inspection regime under the larger agreement. The deal outlines a procedure of up to 24 days for the IAEA to obtain full access to any current nuclear site, including military installations, with provisions for reimposition of sanctions if Iran does not comply.

In a statement Thursday, Sen. Bob Corker (R-Tenn.), chairman of the Foreign Relations Committee, said the IAEA’s “unorthodox agreements speak to how far” U.S.-led negotiators “were willing to go to keep from offending the Ayatollah” Ali Khamenei, Iran’s supreme leader.

“It’s a wonderful talking point for opponents of the deal,” said Jeffrey Lewis, a nonproliferation expert at the Monterey Institute of International Studies and Stanford University. “It’s not ethical, but it’s in­cred­ibly effective.”

Administration officials say they are hamstrung on defending the IAEA arrangement on PMDs because of its confidentiality, and suggest that Republicans have leaked, and misrepresented, information obtained in classified briefings.

In his statement, IAEA head Amano said that he had a “legal obligation” not to make public the PMD arrangements, which he described as “technically sound
and consistent with our long-
established practices. They do not compromise our safeguards standards in any way.”

David Albright, head of the Washington-based Institute for Science and International Security, emphasized that no one outside the IAEA and Iran knows for certain what the PMD agreement on Parchin says. Reports indicate, he said in a statement, that Iran will take samples, photographs and videos at IAEA-designated locations, using authenticated equipment. Amano will then visit the site and the two sides will hold a “roundtable.”

Albright said that the arrangement was “worrisome as a precedent,” should Iran then balk at full IAEA inspections of possible future activity at Parchin.

Meanwhile, Britain, one of the negotiators of the Iran deal, said that Foreign Secretary Philip Hammond would reopen its embassy in Tehran on Sunday, four years after it was closed following a mob attack. Senior German, French and Italian diplomats have also visited the Iranian capital in recent weeks.