VIENNA/TEHRAN, 23 August 2007 — A nuclear cooperation pact Iran struck with the International Atomic Energy Agency has “real limitations” and Tehran should stop trying to manipulate the IAEA to dodge harsher UN sanctions, a senior US envoy said.

Washington was not impressed by Iran’s transparency promise — hailed as a “milestone” by the IAEA on Tuesday — to allay suspicions it is secretly seeking atomic bombs, and would still pursue talks on more UN sanctions against Tehran, the US envoy to the UN nuclear watchdog, Gregory Schulte, said.

The IAEA declined comment on Schulte’s criticism. A diplomat close to the agency said Schulte’s remarks “shows a deliberate campaign to derail this process.” Schulte said Washington welcomed any progress in resolving troubling questions about Iran’s nuclear activities.

“But we understand there are real limitations with the plan, including Iran’s continued refusal to implement the IAEA’s Additional Protocol,” he told reporters by conference call.

He was citing a measure allowing inspectors to conduct spot checks at sites not declared to be nuclear but regarded as important to resolving four-year-old IAEA investigations into the scope and nature of Iran’s atomic program.

Tuesday’s agreement, which has an undisclosed timetable, is meant to resolve IAEA concerns about intelligence indicating possible illicit military involvement in Iran’s declared drive for peaceful nuclear energy and to improve access for UN inspectors to its underground uranium enrichment plant.

Western diplomats believe Iran is making a display of cooperation to split key world powers over the need for stiffer sanctions — Russia and China are reluctant — and wants to buy time so it can master enrichment capability. Schulte said Iran’s suggestion it would not implement the transparency plan unless the UN Security Council shelved steps to intensify the mild sanctions imposed on the Islamic Republic over its refusal to stop enrichment was unacceptable.

Meanwhile, Iranian-American academic Haleh Esfandiari was yesterday enjoying a first day out of custody after her sudden release from three months in jail but is still unable to leave Iran until her passport is returned.

Esfandiari, 67, was released on Tuesday afternoon on bail of three billion rials ($320,000) from Tehran’s Evin Prison, where she had been detained since early May on accusations of links to a US drive to topple Iran’s rulers.

The move was welcomed as “encouraging news” by the White House, which had repeatedly called for the release of Esfandiari and three other American-Iranians held by Tehran. The future of her case was not immediately clear, with Tehran prosecutors emphasizing that it had not been closed. Moreover, she is still without her passport, which was stolen when she was about to leave Iran in December.

“Technically speaking she can leave the country as the purpose of the bail is that she can leave and return when she wants,” said Esfandiari’s lawyer Shirin Ebadi, the Nobel Peace Prize-winning rights activist. “But as you know her passport has been taken,” she told AFP.

Iranian television late on Tuesday showed pictures of Esfandiari as she left Evin Prison in northern Tehran, saying she was happy to be released and that conditions in jail had been good. “They treated me very well in the section. I had a room, it was very big, it had a window. I could have air whenever I wanted. The food was very good.”